Prepare the Cake Layers:

Preheat your oven to 350°F (175°C). Grease and line two 9-inch round cake pans.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt.

In a large mixing bowl, cream together the butter and granulated sugar until light and fluffy. Add the eggs one at a time, beating well after each addition, then mix in the vanilla extract.

Alternately add the dry ingredients and the milk, beginning and ending with the dry ingredients. Mix just until combined.

Gently fold in the sour cream and crushed raspberries. Divide the batter evenly between the prepared cake pans and bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean.

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

Prepare the Cream Cheese Filling:

In a medium bowl, beat the softened cream cheese and butter until smooth.

Gradually add the powdered sugar and vanilla extract, mixing until smooth and creamy. Set aside.

Make the Raspberry Sauce:

In a small saucepan, combine the raspberries, sugar, and lemon juice. Cook over medium heat, stirring occasionally, until the raspberries break down and the mixture begins to thicken (about 5 minutes).

Stir in the cornstarch slurry and continue cooking for another 1-2 minutes until the sauce thickens. Remove from heat and let it cool.

Make the Whipped Cream Frosting:

In a large bowl, beat the heavy cream, powdered sugar, and vanilla extract together until stiff peaks form. Set aside.

Assemble the Cake:

Place one cake layer on a serving platter. Spread a generous amount of the cream cheese filling on top, followed by a drizzle of the raspberry sauce.

Place the second cake layer on top and frost the entire cake with the whipped cream frosting. For extra flair, you can pipe a decorative border around the edges of the cake.

Drizzle more raspberry sauce over the top of the cake and garnish with fresh raspberries if desired.