To prepare a tres leches coconut cupcakes with dulce de leche buttercream recipe, first you need to prepare the cupcake batter. First, you'll need 2 cups of flour, 1 cup of cocoa powder, and 1 teaspoon of baking powder. Then, add the wet ingredients to the dry ingredients and mix them together until the batter is just combined. Next, pour in the coconut milk and beat it with an electric mixer until it's light and fluffy. Add the vanilla extract and stir it in. Now, take the butter and cream cheese mixture and whip it until soft peaks form. Pour the mixture into cupcake liners and bake for 18 to 20 minutes or until toothpick inserted into the center comes out clean.