I still remember the first time I made this Grilled Mozzarella Sandwich with Walnut Pesto. It was a grey, drizzly afternoon, and the usual comfort food cravings were hitting hard. I’d always loved a classic grilled cheese, but I wanted something… more. Something with a bit of a gourmet flair, a punch of flavor that would elevate it beyond a simple childhood staple. I had some fresh basil threatening to wilt, a bag of walnuts in the pantry, and a beautiful ball of fresh mozzarella. The idea sparked: walnut pesto! The aroma that filled my kitchen as the walnuts toasted and then blended with the vibrant basil and sharp Parmesan was an instant mood-lifter. But the real magic happened when that pesto met the creamy, melting mozzarella, all sandwiched between two perfectly golden, buttery slices of sourdough. My family, initially skeptical of “fancying up” a grilled cheese, were converted at first bite. The kids loved the “green cheesy bread,” and my partner declared it the “best grilled cheese, ever.” It’s since become a household favorite, a go-to for a quick yet satisfying lunch, a light dinner with a side salad, or even cut into wedges for a casual appetizer when friends drop by. It’s a testament to how simple ingredients, thoughtfully combined, can create something truly special.

Grilled Mozzarella Sandwich with Walnut Pesto: The Ultimate Gourmet Comfort Food

This isn’t just any grilled cheese. This is an experience. The earthy, slightly sweet crunch of homemade walnut pesto, combined with the luscious, milky melt of fresh mozzarella, all encased in perfectly grilled, crispy bread, creates a symphony of textures and flavors. It’s sophisticated enough for a dinner party appetizer and simple enough for a weeknight treat. Prepare to elevate your sandwich game!

Ingredients: Crafting Your Culinary Masterpiece

To create this delightful sandwich, you’ll first need to prepare the star: the walnut pesto. Then, we’ll assemble and grill the sandwiches to perfection.

For the Walnut Pesto (Yields approximately 1 cup):

Walnuts: 1 cup, raw, shelled halves or pieces
Fresh Basil Leaves: 2 cups, packed (preferably Genovese basil)
Parmesan Cheese: ½ cup, freshly grated (Parmigiano-Reggiano recommended for best flavor)
Garlic: 2 medium cloves, roughly chopped
Extra Virgin Olive Oil: ½ cup, plus more if needed for consistency
Lemon Juice: 1 tablespoon, freshly squeezed
Sea Salt: ½ teaspoon, or to taste
Black Pepper: ¼ teaspoon, freshly ground, or to taste

For the Grilled Mozzarella Sandwiches (Serves 4):

Artisan Bread: 8 slices, about ½ to ¾ inch thick (sourdough, ciabatta, or a good rustic white bread work beautifully)
Fresh Mozzarella Cheese: 16 ounces (two 8-ounce balls), sliced into ¼-inch thick rounds
Walnut Pesto: Approximately ¾ to 1 cup (from the recipe above)
Unsalted Butter: 4 tablespoons, softened (or use a good quality olive oil for brushing)

Instructions: Bringing Your Sandwich to Life

Follow these steps carefully for pesto perfection and the ultimate grilled cheese experience.

Part 1: Making the Walnut Pesto

Toast the Walnuts: Preheat your oven to 350°F (175°C). Spread the walnuts in a single layer on a baking sheet. Toast for 5-8 minutes, or until fragrant and lightly browned. Keep a close eye on them as nuts can burn quickly. Alternatively, you can toast them in a dry skillet over medium heat for 3-5 minutes, stirring frequently. Let them cool slightly. This step is crucial as toasting enhances the nutty flavor and reduces any bitterness.
Prepare Basil: Gently wash and thoroughly dry the basil leaves. A salad spinner works wonders here. Excess water can make your pesto watery and less vibrant.
Combine Ingredients: In the bowl of a food processor, combine the toasted walnuts, packed basil leaves, freshly grated Parmesan cheese, and chopped garlic.
Pulse: Pulse the mixture several times until the ingredients are finely chopped and well combined. Scrape down the sides of the bowl as needed.
Emulsify with Olive Oil: With the food processor running on low, slowly drizzle in the extra virgin olive oil. Continue processing until the pesto is smooth but still has a little texture. If you prefer a looser pesto, you can add a tablespoon or two more olive oil or even a tiny bit of warm water.
Season: Add the fresh lemon juice, sea salt, and freshly ground black pepper. Pulse a few more times to combine. Taste and adjust seasoning if necessary. The lemon juice brightens the flavors and helps keep the pesto green.
Store (if not using immediately): If you’re not using the pesto right away, transfer it to an airtight container. To prevent browning, you can pour a thin layer of olive oil over the surface or press plastic wrap directly onto the pesto. It can be stored in the refrigerator for up to 5 days or frozen for up to 3 months.

Part 2: Assembling and Grilling the Mozzarella Sandwiches

Prepare Bread and Cheese: Lay out your 8 slices of bread. If your mozzarella balls are packed in water, pat them dry with paper towels before slicing. This prevents a soggy sandwich.
Spread Pesto: Generously spread a layer of the homemade walnut pesto on one side of each of the 8 bread slices. The amount is up to your preference, but about 1.5 to 2 tablespoons per slice works well.
Layer Mozzarella: On 4 of the pesto-covered bread slices, arrange the fresh mozzarella slices, covering the surface evenly. Don’t be shy with the cheese!
Form Sandwiches: Top the cheese-laden slices with the remaining 4 pesto-covered bread slices, pesto-side down, to form 4 sandwiches.
Butter the Outside: Lightly spread softened butter on the outside of both top and bottom slices of each sandwich. Alternatively, you can brush the outside with olive oil for a slightly different flavor and crispness.
Grill the Sandwiches:
- Stovetop Method (Recommended): Heat a large skillet, griddle, or pan (cast iron works exceptionally well) over medium-low heat. Once hot, place the sandwiches in the skillet. You may need to cook them in batches depending on the size of your pan.
- Grill Press/Panini Maker: If using a panini press, preheat it according to manufacturer’s instructions and grill until golden and cheese is melted.
Cook to Perfection: Grill the sandwiches for about 3-5 minutes per side. The key is “low and slow” to ensure the bread becomes golden brown and crispy, and the mozzarella melts completely without the bread burning. Press down gently with a spatula occasionally for even browning.
Check for Doneness: The sandwiches are ready when the bread is a beautiful golden-brown color, and the mozzarella is ooey-gooey and melted. You should see it peeking out from the sides.
Rest and Serve: Remove the sandwiches from the skillet and let them rest for a minute or two before slicing. This allows the cheese to set slightly, making them easier to cut and less likely to ooze everywhere immediately. Slice diagonally and serve warm.

Nutrition Facts

Servings: 4 sandwiches
Calories per serving (approximate): 750-850 calories

Disclaimer: Nutritional information is an estimate and can vary significantly based on specific ingredients used (brand, fat content of cheese, type of bread, amount of oil/butter). This estimate includes one sandwich made with approximately 2 tablespoons of pesto, 4 ounces of fresh mozzarella, two slices of standard artisan bread, and 1 tablespoon of butter for grilling.

Breakdown (Approximate per sandwich):

Bread (2 slices): 200-250 calories
Fresh Mozzarella (4 oz): 280-320 calories
Walnut Pesto (2 tbsp): 150-180 calories
Butter (1 tbsp for grilling): 100-120 calories

This sandwich is a decadent treat, rich in healthy fats from walnuts and olive oil, protein from cheese and nuts, and carbohydrates from the bread.

Preparation Time

Understanding the time commitment helps in planning your meal perfectly.

For the Walnut Pesto:
- Active Prep Time: 10 minutes (chopping garlic, measuring, washing basil)
- Toasting Walnuts: 5-8 minutes
- Processing Time: 5 minutes
- Total Pesto Time: Approximately 20-25 minutes
For the Grilled Sandwiches:
- Assembly Time: 5-7 minutes
- Grilling Time: 6-10 minutes per batch (depending on pan size)
- Total Sandwich Time (assuming 2 batches): 17-27 minutes
Overall Estimated Time (Pesto + Sandwiches made sequentially): 40-55 minutes

If you make the pesto ahead of time, the sandwiches themselves come together in under 30 minutes, making for a quick and impressive meal.

How to Serve: Elevating Your Grilled Mozzarella Experience

This Grilled Mozzarella Sandwich with Walnut Pesto is fantastic on its own, but here are some ideas to turn it into a complete and memorable meal or a standout appetizer:

Classic Comfort Combo:
- Serve alongside a steaming bowl of creamy tomato soup. The acidity of the tomato beautifully cuts through the richness of the sandwich. A rustic, chunky tomato basil soup would also be divine.
Fresh & Light Pairings:
- A simple arugula salad dressed with lemon vinaigrette and shaved Parmesan. The peppery arugula complements the nutty pesto.
- A mixed greens salad with cherry tomatoes, cucumbers, and a light balsamic glaze.
For a Heartier Meal:
- Alongside roasted vegetables like bell peppers, zucchini, and red onion.
- With a side of sweet potato fries or crispy potato wedges.
Appetizer Style:
- Cut the sandwiches into small triangles or “fingers” and arrange them on a platter.
- Serve with a small bowl of extra pesto for dipping.
- Offer a side of marinara sauce for an Italian-inspired dip.
Gourmet Touches:
- Drizzle a tiny bit of balsamic glaze over the sandwich just before serving for an extra layer of tangy sweetness.
- Garnish with a fresh basil sprig for visual appeal and aroma.
Drink Pairings:
- Wine: A crisp Sauvignon Blanc, a dry Rosé, or a light-bodied Pinot Grigio would pair wonderfully.
- Beer: A light lager or a pale ale.
- Non-alcoholic: Freshly squeezed lemonade, sparkling water with a lemon twist, or a classic iced tea.

Additional Tips for Sandwich Perfection

Unlock the full potential of your Grilled Mozzarella Sandwich with these expert tips:

Bread Choice is Key: Use a sturdy, good-quality bread that can hold up to the fillings and grilling. Sourdough offers a pleasant tang, ciabatta has great texture, and a rustic Italian loaf provides a hearty bite. Avoid flimsy, pre-sliced sandwich bread as it can become soggy. Slice it yourself to about ½ to ¾ inch thickness.
Quality Mozzarella Matters: Opt for fresh mozzarella (the kind sold in a ball, often packed in water) for the best melt and creamy texture. Low-moisture mozzarella will also work and gives a stringier pull, but fresh mozzarella offers a superior milky flavor. Always pat it dry before slicing!
Don’t Overstuff, But Be Generous: While it’s tempting to load up on cheese and pesto, overstuffing can lead to a messy sandwich where the fillings ooze out excessively during grilling. Find a good balance – enough for flavor and melt, but not so much that it becomes unmanageable.
Low and Slow Grilling is Crucial: Medium-low heat is your friend. This allows the bread to toast to a perfect golden brown and become wonderfully crisp, while giving the mozzarella ample time to melt completely through without burning the exterior. Rushing the process on high heat will result in burnt bread and unmelted cheese.
Pesto Power-Ups & Variations:
- Nut Variations: While this recipe calls for walnuts, feel free to experiment with other nuts like pistachios (for a vibrant green and unique flavor), almonds, or even sunflower seeds for a nut-free version. Always toast them first!
- Herb Twists: Substitute half the basil with fresh spinach or arugula for a different flavor profile. A touch of fresh mint or parsley can also add complexity.
- Spice it Up: Add a pinch of red pepper flakes to your pesto for a subtle kick of heat.

FAQ: Your Grilled Mozzarella Sandwich Questions Answered

Q1: Can I make the walnut pesto ahead of time?
A: Absolutely! Walnut pesto can be made up to 5 days in advance. Store it in an airtight container in the refrigerator. To prevent browning, pour a thin layer of olive oil over the surface or press plastic wrap directly onto the pesto before sealing the container. You can also freeze pesto for up to 3 months. Thaw it in the refrigerator overnight before using.

Q2: Can I use a different type of cheese?
A: While fresh mozzarella is recommended for its creamy melt and mild flavor that complements the pesto perfectly, you can certainly experiment. Provolone, Fontina, or even a good quality Havarti would also melt well and offer different flavor notes. A combination of mozzarella and provolone can be delicious. However, the classic mozzarella is hard to beat for this particular sandwich.

Q3: How can I make this sandwich gluten-free?
A: Easily! Simply substitute the artisan bread with your favorite gluten-free bread. Look for a sturdy gluten-free loaf that grills well. The walnut pesto itself is naturally gluten-free. Ensure your Parmesan cheese is also certified gluten-free if Celiac disease is a concern (most pure Parmesan is, but check labels).

Q4: What’s the best way to store and reheat leftover sandwiches?
A: Leftover grilled mozzarella sandwiches are best enjoyed fresh, but if you have leftovers, wrap them tightly in foil or store them in an airtight container in the refrigerator for up to 2 days. To reheat, the best method is in a skillet over low heat (similar to how you cooked it initially) to re-crisp the bread and re-melt the cheese. You can also use an oven or toaster oven at around 350°F (175°C) for 5-10 minutes, or an air fryer for a few minutes until heated through and crispy. Avoid the microwave, as it will make the bread soggy.

Q5: Why use walnuts in pesto instead of traditional pine nuts?
A: Walnuts offer a wonderful alternative to pine nuts for several reasons. They have a distinct earthy, slightly sweet, and robust flavor that pairs beautifully with basil and Parmesan. They also provide a creamier texture when blended. Furthermore, walnuts are often more readily available and can be more budget-friendly than pine nuts. Toasting the walnuts before adding them to the pesto is key to bringing out their best flavor and reducing any potential bitterness.

Grilled Mozzarella Sandwich with Walnut Pesto Recipe