1. Prepare the Cake Layers:

• Preheat and Prep: Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans. Line the bottoms with parchment paper rounds for easier removal.
• Combine Dry Ingredients: In a medium bowl, whisk together the cake flour, baking powder, baking soda, and salt. Set aside.
• Cream Butter and Sugar: In a large mixing bowl, using an electric mixer (stand mixer with paddle attachment or hand mixer), cream together the softened butter and granulated sugar until light and fluffy (about 3-4 minutes).
• Add Eggs and Vanilla: Add the room-temperature eggs one at a time, beating well after each addition until fully incorporated. Mix in the vanilla extract.
• Alternate Dry Ingredients and Milk: Reduce the mixer speed to low. Gradually add the dry ingredients to the butter mixture in three additions, alternating with the room-temperature milk in two additions (begin and end with the dry ingredients). Mix until just combined after each addition. Do not overmix.
• Fold in Sour Cream and Raspberries: Gently fold in the room-temperature sour cream and the crushed fresh raspberries using a rubber spatula until evenly incorporated.
• Bake: Divide the batter evenly between the prepared cake pans and smooth the tops. Bake for 25-30 minutes, or until a wooden toothpick inserted into the center comes out clean.
• Cool: Allow the cakes to cool in the pans for 10 minutes before inverting them onto a wire rack to cool completely. Ensure cakes are completely cool before assembling and frosting.

2. Prepare the Cream Cheese Filling:

• In a medium bowl, using an electric mixer, beat the softened cream cheese and softened butter together until smooth and creamy.
• Gradually add the powdered sugar and vanilla extract, mixing on low speed until combined, then increase speed and beat until smooth and fluffy. Set aside.

3. Make the Raspberry Sauce:

• In a small saucepan, combine the 1 cup fresh raspberries, granulated 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 (1 tablespoon cornstarch mixed with 2 tablespoons cold water). Continue cooking, stirring constantly, for another 1-2 minutes until the sauce thickens.
• Remove from heat and let the sauce cool completely.

4. Make the Whipped Cream Frosting:

• In a chilled large bowl, using chilled beaters (or the whisk attachment of a stand mixer), beat the very cold heavy whipping cream, powdered sugar, and vanilla extract together on medium-high speed until stiff peaks form. Be careful not to overbeat.

5. Assemble the Cake:

• First Layer: Place one cooled cake layer on a serving platter or cake stand. Spread a generous amount of the cream cheese filling evenly over the top. Drizzle some of the cooled raspberry sauce over the cream cheese filling.
• Second Layer: Carefully place the second cooled cake layer on top.
• Frost: Frost the entire cake (top and sides) with the prepared whipped cream frosting. You can create swirls or use a piping bag for decorative borders if desired.
• Garnish: Drizzle more raspberry sauce over the top of the cake and garnish with fresh raspberries, if desired.
• Chill (Recommended): For best results and easier slicing, chill the assembled cake in the refrigerator for at least 30 minutes before serving.