Step 1: Prepare the Pan and Caramel Base

1. Preheat your oven to 350°F (175°C). This ensures the oven is at the correct temperature before the cake goes in.
2. Grease and flour a 9×13 inch baking pan. This prevents the cake from sticking to the pan and allows for easy removal after baking. You can also use baking spray with flour for convenience.
3. Melt ½ cup (1 stick) of unsalted butter in the baking pan in the oven or on the stovetop over low heat. Melting the butter directly in the pan saves a dish and ensures even caramelization. Be careful not to let the butter burn.
4. Remove the pan from the oven or stovetop. If you melted butter on the stovetop, ensure the pan is oven-safe before placing it in the oven later.
5. Sprinkle ¾ cup packed light brown sugar evenly over the melted butter in the pan. Distribute the brown sugar in a uniform layer to ensure even caramelization.
6. Arrange pineapple slices in a single layer over the brown sugar. Create a visually appealing pattern. You can use whole slices or cut them in half or quarters to fit the pan.
7. Place halved maraschino cherries in the centers of the pineapple slices and in any gaps between the slices (optional). This adds color and sweetness.

Step 2: Prepare the Cake Batter

1. In a large bowl, whisk together 2 ½ cups all-purpose flour, 1 ½ cups granulated sugar, 3 ½ teaspoons baking powder, and 1 teaspoon salt. Whisking ensures the dry ingredients are evenly combined and prevents lumps.
2. In a separate bowl, combine ½ cup (1 stick) softened unsalted butter, 1 cup whole milk, 2 large eggs, and 2 teaspoons vanilla extract. Whisk until well combined and smooth.
3. Gradually add the wet ingredients to the dry ingredients, mixing on low speed with an electric mixer (or by hand) until just combined. Be careful not to overmix the batter. Overmixing can lead to a tough cake. Mix until there are no large streaks of flour remaining. A few small lumps are okay.
4. Increase the mixer speed to medium and beat for 1-2 minutes until the batter is smooth and well combined. This develops the gluten slightly and creates a cohesive batter.

Step 3: Bake the Cake

1. Carefully pour the cake batter evenly over the pineapple and caramel layer in the prepared pan. Spread the batter gently to cover the pineapple completely.
2. Bake in the preheated oven for 30-35 minutes, or until a wooden skewer inserted into the center of the cake comes out clean. Baking times may vary slightly depending on your oven. Start checking for doneness around 30 minutes.
3. Let the cake cool in the pan for 10-15 minutes. This is crucial! Cooling allows the caramel to slightly thicken and makes inverting the cake easier and less messy. If you invert it too soon, the caramel may be too runny.

Step 4: Invert and Serve

1. Run a thin knife or spatula around the edges of the cake to loosen it from the pan. This helps prevent sticking when inverting.
2. Place a serving platter or large cutting board upside down over the baking pan.
3. Holding the platter and pan firmly together, quickly and carefully invert the cake onto the platter. Be cautious as the pan will be hot, and some hot caramel may drip.
4. Gently tap the bottom of the pan to release the cake completely.
5. If any pineapple slices or cherries stick to the pan, carefully arrange them back onto the cake.
6. Serve warm or at room temperature.