Preheat your oven to 350F (175C) and prepare two 9-inch round cake pans by greasing and flouring them.

In a mixing bowl, cream together the butter and sugar. Add the eggs one at a time, beating thoroughly after each.

Lightly coat the raspberries with a bit of flour to prevent them from sinking to the bottom, then fold them into the batter along with the raspberry preserves.

In a separate bowl, combine flour, baking soda, and salt. Alternately add the dry mixture and buttermilk to the creamed butter mixture, starting and ending with the dry ingredients.

Stir in the vinegar and, if desired, add red food coloring until you achieve the desired shade.

Divide the batter evenly between the prepared pans and bake for about 25 minutes, or until a toothpick inserted in the center comes out clean.

For the frosting, beat the butter and cream cheese until smooth and creamy. Gradually add the powdered sugar and vanilla extract, beating until the frosting is light and fluffy. Tint with red food coloring if desired.

Once the cakes are completely cool, frost each layer and stack them. Decorate with fresh raspberries for a beautiful finish.