Step 1: Prepare the Crust

1. Combine Dry Ingredients: In a large bowl, whisk together the flour and salt.
2. Cut in the Butter: Add the cold, cubed butter to the flour mixture. Using a pastry blender or your fingertips, cut the butter into the flour until the mixture resembles coarse crumbs with some pea-sized pieces of butter remaining. The goal is to keep the butter cold and create layers for a flaky crust.
3. Add Ice Water: Gradually add the ice water, one tablespoon at a time, mixing gently after each addition. Mix until the dough just comes together and forms a shaggy ball. Be careful not to overmix.
4. Form a Disc and Chill: Turn the dough out onto a lightly floured surface and gently form it into a disc about 1-inch thick. Wrap the disc tightly in plastic wrap and refrigerate for at least 30 minutes, or up to 2 hours. Chilling the dough allows the gluten to relax, making it easier to roll out and prevents shrinkage during baking.

Step 2: Roast the Vegetables

1. Preheat Oven and Prepare Baking Sheet: Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper for easy cleanup.
2. Toss Vegetables with Oil and Seasonings: In a large bowl, combine the red bell pepper, yellow bell pepper, zucchini, red onion, minced garlic, olive oil, dried thyme, dried rosemary, salt, and pepper. Toss well to ensure all vegetables are evenly coated with oil and seasonings.
3. Roast the Vegetables: Spread the vegetables in a single layer on the prepared baking sheet. Roast in the preheated oven for 20-25 minutes, or until the vegetables are tender and slightly caramelized, stirring halfway through. Roasting time may vary depending on your oven and the size of the vegetable pieces. Keep an eye on them to prevent burning.
4. Cool Slightly: Remove the roasted vegetables from the oven and let them cool slightly while you prepare the crust and filling.

Step 3: Blind Bake the Crust

1. Roll Out the Dough: Remove the chilled dough from the refrigerator. On a lightly floured surface, roll out the dough into a 12-inch circle, about ⅛-inch thick.
2. Transfer to Pie Plate: Gently transfer the rolled-out dough to a 9-inch pie plate. Press the dough into the bottom and up the sides of the pie plate. Trim any excess dough hanging over the edge and crimp the edges as desired.
3. Dock the Crust: Prick the bottom of the crust all over with a fork. This prevents the crust from puffing up during blind baking.
4. Line and Fill with Weights: Line the crust with parchment paper or aluminum foil and fill with pie weights, dried beans, or rice. This will weigh down the crust and prevent it from shrinking or slumping during baking.
5. Blind Bake: Bake in the preheated oven for 15 minutes.
6. Remove Weights and Bake Further: Carefully remove the parchment paper and pie weights. Return the crust to the oven and bake for another 10-12 minutes, or until the crust is lightly golden brown. This par-baking ensures the crust is cooked through and prevents a soggy bottom when the filling is added.
7. Cool Slightly: Remove the crust from the oven and let it cool slightly while you prepare the filling.

Step 4: Prepare the Quiche Filling

1. Whisk Eggs and Dairy: In a large bowl, whisk together the eggs, heavy cream, and milk until well combined.
2. Add Cheese and Parsley: Stir in the crumbled chevre, grated Gruyere cheese, and chopped parsley.
3. Season the Filling: Season the filling with salt and pepper to taste. Remember that the chevre and Gruyere are already somewhat salty, so taste before adding too much salt.

Step 5: Assemble and Bake the Quiche

1. Arrange Roasted Vegetables in Crust: Spread the roasted vegetables evenly over the bottom of the pre-baked quiche crust.
2. Pour Filling Over Vegetables: Gently pour the prepared egg and cheese filling over the roasted vegetables, ensuring it is evenly distributed.
3. Bake the Quiche: Bake in the preheated oven at 350°F (175°C) for 35-45 minutes, or until the quiche is set and the center is just slightly jiggly. The edges should be golden brown and the filling should be puffed and set. A knife inserted into the center should come out mostly clean.
4. Cool Slightly and Serve: Remove the quiche from the oven and let it cool for at least 10-15 minutes before slicing and serving. This allows the filling to set further and makes it easier to slice.