Step 1:Prepare the Pans: Preheat your oven to 350°F (175°C). Grease and flour three 9-inch round cake pans. Line the bottom of each cake pan with parchment paper to ensure easy removal after baking.

Step 2: Separate the Eggs
Gently separate the egg whites from the yolks. Set the yolks aside for later use.

Step 3: Beat the Egg Whites
In a clean mixing bowl, whisk the egg whites until soft peaks form. Set aside.

Step 4: Mix the Dry Ingredients
In a large bowl, sift together the flour, baking powder, baking soda, and salt.

Step 5: Add Yolks and Vanilla
Blend the reserved egg yolks and vanilla extract into the butter-sugar mixture until smooth and well incorporated.

Step 6: Combine Wet and Dry Ingredients
Alternately add the sifted dry ingredients and buttermilk to the creamed mixture, starting and ending with the dry ingredients. Mix just until combined—do not overmix.

Step 7: Add the Raspberries
Fold the mashed black raspberries gently into the batter until evenly distributed.

Step 8: Divide and Bake
Pour the batter evenly into the prepared pans. Bake in the preheated oven for 20–25 minutes, or until a toothpick inserted into the center of the cakes comes out clean.

Step 9:Cool: Allow the cakes to cool in the pans for 5 minutes before transferring them to wire racks to cool completely.

Step 10:Prepare the Frosting: In a mixing bowl, beat the cream cheese and butter until smooth. Frosting Tip
Gradually add 4 cups of powdered sugar to the cream cheese and butter mixture, beating until smooth and creamy. Add the crushed black raspberries and vanilla extract, mixing well. Continue adding powdered sugar until the frosting reaches a spreadable consistency.

Step 11:Assemble the Cake: Place one cake layer on a serving plate. Spread a layer of frosting on top. Repeat with the remaining layers. Frost the sides and top of the cake, creating decorative swirls as desired.

Step 12:Chill: Refrigerate the cake until ready to serve, allowing the frosting to set.