Chocolate Yema Cupcakes with Chocolate Ganache Frosting

Preheat oven to 325ºF. Line a 3-ounce, 12-cavity muffin tin with cupcake liners.

Sift together cocoa, flour, baking soda, baking powder, and salt in a bowl. Set aside.

Combine milk and vinegar in a bowl. Let stand, undisturbed, for 5 to 10 minutes.

Cream together butter and sugar until light and fluffy, 3 to 5 minutes. Add egg, egg yolks, and coffee; beat until well-combined. Add milk-vinegar mixture and mix again.

Add dry ingredients all at once and mix just until combined. Be sure to scrape the bottom and sides of the bowl.

Spoon batter into prepared muffin tin and bake for 18 to 20 minutes. Allow cupcakes to cool for 5 to 10 minutes in the pan before cooling completely on a cooling rack.

Prepare the yema filling: Place all ingredients in a small saucepot and stir constantly over medium heat. It is important to keep stirring the mixture as it burns easily. Cook for 10 to 15 minutes or until slightly thickened. Allow to cool completely before using.

Make the whipped ganache: Place chocolate in a clean, dry bowl. Scald heavy cream and pour over chocolate. Allow to stand for 1 to 2 minutes. Stir until it comes together and no chunks remain; add salt. Allow to cool and thicken for 15 to 20 minutes. Using a handheld mixer, whip ganache until fluffy.

Assemble the cupcakes: Using a sharp knife, score and scoop out a circle in the middle of each cupcake and spoon yema filling inside. Transfer whipped ganache in a piping bag with a star tip and pipe frosting on cupcakes.