1-First, grease and flour three 8-inch round pans or line them with parchment paper for easy removal. In a large bowl, sift the cocoa powder over the combined flour (not explicitly listed but implied in the dry mix), sugar, baking powder, baking soda, and salt, then stir to blend everything well. Add the softened butter and mix at low speed for about one minute until it incorporates.

2-With the mixer still running, add the vegetable oil and continue mixing until the mixture resembles sand, which takes around one minute. In another bowl, combine the vanilla extract with the milk and coffee or water, then add this liquid all at once to the dry ingredients. Mix at low speed for one minute, scrape the bowl sides and bottom, and mix for another 30 seconds to ensure it’s even.

3-Next, add the eggs one at a time, beating well at medium-high speed after each addition for full integration. Scrape the bowl sides again and mix for one more minute to create a smooth batter. This step is crucial for that light, airy texture we all love in a chocolate cake.

4-Divide the batter evenly among the prepared pans and smooth the tops for an even rise. Bake for 20 to 25 minutes, checking for doneness by lightly touching the center it should spring back, and a toothpick inserted should come out clean. Let the cakes cool in the pans for 5 minutes, then remove and cool completely on wire racks.

5-For the filling, whisk together 1 cup dulce de leche and ¼ cup heavy cream until smooth and creamy. For the ganache, heat 1 cup heavy cream just to a boil, pour it over 16 ounces of finely chopped milk chocolate, let it sit for two minutes, then stir until smooth. Cool the ganache until it’s thick but spreadable, stirring every 10 minutes if refrigerated.

6-To assemble, place one cake layer on a serving plate and spread half the dulce de leche filling evenly on top. Add the second layer and spread the remaining filling, then top with the third layer. Finally, spread the cooled ganache over the top and sides, and if you like, drizzle any leftover dulce de leche for extra flair. The total time is about 1 hour 30 minutes, with 1 hour 10 minutes for prep and 20 minutes for cooking, yielding 12 to 16 servings.