Preheat oven to 350ºF. Lightly grease three 8″ pans. Line with a circle of parchment paper, cut to fit the pan, and then grease the parchment paper circle. I don’t recommend skipping this step or your cakes could stick to the bottom of the pan. Set pans aside.

Vanilla Cake Layer:

In a large mixing bowl, combine flour(s), sugar, baking powder, baking soda, and salt. Add milk, oil, vinegar, and vanilla extract, mixing just until smooth.

Pour batter into one of the prepared pans and place in the oven on middle rack.

Bake for 22–28 minutes, or just until center is set and a toothpick inserted near the center comes out mostly clean. Let cake cool in pans before frosting.

Cakes can even be made a few days beforehand, wrapped well after thoroughly cooled, and frozen until needed. It actually makes them easier to frost if they’re frozen.

Chocolate Cake Layers:

In the same mixing bowl as the vanilla cake (no need to wash) combine flour, sugar, cocoa powder, baking powder, baking soda, and salt. Mix in milk, coffee, oil, and vanilla, beating just until batter is smooth.

Pour batter into remaining two prepared pans and place onto middle rack of oven. Bake for 22–28 minutes, or just until center is set and a toothpick inserted comes out mostly clean. Bake time varies depending on your pans and your oven.

Let cakes cool completely before frosting.

Vanilla Buttercream:

In a large bowl, beat softened butter until creamy. Add powdered sugar 1 cup at a time, alternating with vanilla and 2–3 tablespoons of milk, blending until well combined. Beat in additional milk if buttercream is too stiff.

Putting the Cake Together:

Let cakes cool for several minutes in the pan before inverting onto a cooling rack to cool thoroughly. Cakes are the easiest to frost when they are wrapped in plastic wrap (wrapped well to avoid frost bite) and frozen on a flat surface in your freezer overnight.

To decorate, place a chocolate cake layer upside down on a decorative stand or plate. To keep the plate clean, you can tuck strips of parchment paper under the cake to catch the frosting.

Use an offset spatula to spread a big dollop buttercream evenly across cake layer. Top with berry slices, then the vanilla layer of cake. Repeat steps with remaining chocolate layer.

Cover the tops and sides of the cake with a thin layer of buttercream. Thin meaning you should still be able to see the cake. This is called a crumb coat, which seals in the crumbs and keeps the cake moist. Pop it in the fridge for at least 30 minutes so the frosting can firm up.

Once the frosting has firmed up, use a clean spatula to spread the rest of the buttercream oven the top and sides of the cake. Remove parchment paper and serve. If cakes were previously frozen, let it sit at room temperature for 2–3 hours before serving.

Cover leftover cake well and store in the refrigerator. Because of the fresh berries, the cake is best if enjoyed within 2–3 days.