Preheat your oven to 350°F (175°C) and grease two 9-inch cake pans. In a large bowl, sift together 2 cups of flour, 1.5 cups of sugar, 2.5 teaspoons of baking powder, and 0.5 teaspoon of salt.

In a separate bowl, whisk together 3 large eggs, 1 cup of whole milk, and 2 teaspoons of vanilla extract.

Gradually pour wet ingredients into the dry ingredients, stirring until just combined.

Divide the batter evenly between the prepared pans and bake in the preheated oven for 25-30 minutes.

Allow the cakes to cool in the pans for about 10 minutes, then transfer to a wire rack to cool completely.

In a medium saucepan, combine 2 cups of raspberries, 0.5 cup of sugar, and 2 tablespoons of cornstarch over medium heat.

Stir continuously until thickened, about 5-7 minutes, then let cool.

Beat 1 cup of unsalted butter until creamy, then gradually add 4 cups of powdered sugar alternating with 0.25 cup of heavy cream.

Mix in 2 teaspoons of vanilla extract and blue food coloring if desired.

Place one cooled cake layer on a serving plate and spread raspberry filling over the top.

Add the second layer on top and apply a thin layer of frosting, then refrigerate for 15 minutes.

Cover the cake with remaining frosting and decorate as desired.