Preheat oven to 350 degrees F. Insert cupcake liners into a muffin tin.

In a small bowl, whisk together the milk, eggs, and vanilla.

In another bowl, sift the flour, sugar, dark cocoa powder, baking powder, baking soda, and salt.

Add the butter and half of the milk mixture into the dry ingredients and stir until the dry ingredients are moistened.

With a mixer, mix on medium low for about 45 seconds. Add the rest of the milk mixture, and mix on medium low for another 20 seconds.

Divide the cupcake batter between the cupcake liners. Fill about 2/3 full.

Bake at 350 degrees F for about 18-20 minutes or until a toothpick inserted in the center comes out clean or with a just a few crumbs.

Allow cupcakes to cool completely before adding sprinkles or frosting.

When cupcakes are cool, or while they are cooling, make up the frosting.

Microwave the dark chocolate chips in a glass dish for 2 to 3 minutes on 50% power, until they are shiny.

Remove from microwave and stir contentiously and rapidly until smooth. Stir in the sour cream. Once combined, stir in the vanilla and salt.

Allow to cool slightly until spreadable.

Cut out a hole in the top of each of the cupcakes. Save the piece. I used a decorators tip to get the cake out and the hole deep enough without going through.

Fill the cupcake with about a tablespoon of sprinkles. Place the circle of cake back on top.

Frost as usual. Top with even more sprinkles.