Preheat your oven to 350°F (175°C) and line a cupcake pan with 12 cupcake liners.

In a medium mixing bowl, sift together the flour, cocoa powder, baking powder, baking soda, salt, and optional espresso powder. Set aside.

In a large bowl, cream the softened butter and sugar together until light and fluffy, about 1-2 minutes.

Add the egg, egg yolk, and vanilla to the butter mixture and beat until pale and fluffy, about 1 minute.

Mix in the milk and sour cream until well combined.

Gradually fold the dry ingredients into the wet ingredients until just combined.

Fill the cupcake liners three-quarters full with batter and bake for 17-20 minutes. Test with a toothpick.

While the cupcakes bake, prepare the ganache by heating the cream and pouring it over chopped chocolate. Stir in preserves until smooth.

For the frosting, beat the softened butter until fluffy, then gradually add powdered sugar, crushed raspberries, and more preserves.

Once cooled, core the cupcakes, fill with ganache, and pipe the raspberry buttercream on top. Garnish with fresh raspberries.