I preheat the oven to 350°F (175°C). I spray two 8-inch or 9-inch cake pans with oil, line with parchment rounds, spray again, and lightly dust with flour to prevent sticking.

In a stand mixer with a whisk or paddle attachment, I combine 2 cups flour, 2 cups sugar, ½ cup cocoa powder, ¼ cup dark cocoa powder, 2 tsp baking powder, 1½ tsp baking soda, and 1 tsp salt. I whisk for 30 seconds. I add 1 cup milk, ½ cup oil, and 2 eggs, mixing on medium speed for 2–3 minutes until just combined. I scrape the bowl, then add 1 cup hot coffee, beating for 1 minute. The batter will be runny.

I divide the batter evenly between the pans and bake for 30–35 minutes, or until a toothpick comes out clean. I cool the cakes in the pans for 10 minutes, then transfer to cooling racks to cool completely.

In a stand mixer with a paddle attachment, I beat 2 cups softened butter for 5 minutes until light. I melt ¼ cup chocolate in the microwave in 30-second increments, stirring until smooth, and cool for 5 minutes. I sift 5–7 cups powdered sugar, adding 1 cup at a time to the butter, mixing until creamy. I add ¼–½ cup cream and beat on medium-high for 3 minutes until fluffy.

I divide the buttercream into three portions. I mix ¼ cup melted chocolate into one portion and ¼ cup strawberry puree into another, leaving the third as vanilla. I adjust sweetness with extra sugar if needed for Neapolitan Chocolate Cake.

I level the cooled cakes if needed, place one layer on a serving plate, and spread with chocolate buttercream. I add the second layer and frost the top with vanilla buttercream and the sides with strawberry buttercream for a classic Neapolitan look.