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

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

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

Add the eggs and vanilla to the butter and sugar mixture and beat until pale and fluffy.

Mix in the milk and sour cream until fully combined.

Gradually add the dry ingredients to the wet mixture, stirring gently until just combined.

Fill each cupcake liner about ¾ full with the batter and bake for 17-20 minutes.

Allow the cupcakes to cool in the pan for about 10 minutes, then transfer to a wire rack to cool completely.

For the ganache, heat the heavy cream until steaming and pour it over the chopped chocolate, letting it sit before stirring until smooth.

Mix in the raspberry preserves and allow the ganache to cool until thickened.

To make the frosting, beat the softened butter until fluffy, then gradually add the powdered sugar, raspberries, and vanilla.

Remove the centers of the cooled cupcakes and fill them with ganache, then pipe the raspberry buttercream on top.

Garnish each cupcake with a fresh raspberry before serving.