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

In a large mixing bowl, sift together all-purpose flour, Dutch process cocoa powder, baking powder, baking soda, salt, and espresso powder (if using).

Cream the room-temperature unsalted butter and granulated sugar using a mixer until fluffy and pale, about 3-4 minutes.

Add one egg, one egg yolk, and vanilla extract to the mixture and beat until well combined, about 2 minutes.

Stir in the whole milk and sour cream until just combined.

Gradually mix in the sifted dry ingredients until no dry flour remains, being careful not to overmix.

Fill each cupcake liner about ¾ full with batter, then bake for 17-20 minutes until a toothpick comes out clean.

Let the cupcakes cool in the pan for 10 minutes before transferring to a wire rack to cool completely.

To prepare the ganache, heat heavy cream until steaming and pour over semi-sweet chocolate. Stir until smooth and mix in raspberry preserves.

Beat softened butter until pale and fluffy, then gradually add powdered sugar, folding in freeze-dried raspberries and more raspberry preserves.

Once cupcakes are cool, remove centers, fill with ganache, and frost with raspberry buttercream.

Decorate with fresh raspberries before serving.