Preheat the oven to 175°C. Line 18 muffin tins with cupcake liners
In a medium bowl whisk together the flour, cocoa powder, Coffee powder, baking powder, baking soda and salt
In the bowl of a stand mixer fitted with the paddle attachment beat the butter and sugar together on high for 1 minute then let stand for 2 minutes; scrape down the sides of the bowl and continue beating for 2 minutes or until the mixture is light in color. Add the eggs one at a time, beating well after each addition. Add the vanilla with the last egg. Scrape down the sides of the bowl as needed.
Reduce mixer speed to low and alternately add flour mixture and sour cream beginning and ending with flour, scraping down the sides of the bowl as needed. I did three additions. You want to stop mixing as soon as the last of the flour has been incorporated.
Mix in the chocolate chips on low speed just until distributed.
Scoop the batter into the prepared muffin tins. The batter should almost reach the top of the liner. I use an ice cream scoop to make this process easier. Bake in preheated oven 12 to 18 minutes or until a toothpick inserted into the center comes out with a few clinging crumbs.
After 2 minutes, remove to a wire rack and let cool completely before filling or frosting.
Ganache : Microwave half and half and chocolate together just until the milk is hot and the chocolate begins to melt. Stir with a spatula until all chocolate is melted and incorporated.
Add the butter and continue to stir until smooth and glossy. You don’t want to stir too much or too vigorously because it will actually whip air into the ganache and we want a nice, thick filling!
Let cool until it is easy to spoon into the cupcakes.
Melt chocolate in a microwave safe bowl in the microwave in 15 second intervals. Stir after each interval, being careful not the over heat it. Add the large pinch of salt and cocoa powder and stir to mix. Set aside to cool slightly.
In the bowl of a stand mixer fitted with the paddle attachment, beat butter until creamy, about 2 minutes. Add your half and half and beat until mixture is light and fluffy, but start on low speed or you will splatter milk everywhere!
Add all the melted chocolate mixture at once and then beat for about 3 minutes. It will start to turn a lighter brown color and you will be able see that the texture has become lighter and more airy.
Add the vanilla and beat to incorporate
In half cup increments add your powdered sugar, beating well to incorporate, scraping down the sides of the bowl after each addition. Beat until it is as light as you would like it. It will firm up as the cupcakes sit at room temperature but it will not harden unless you refrigerate them.
If the consistency is too loose, add a bit more sifted powdered sugar about a tablespoon at a time, beating to incorporate. If it is too stiff you can add more half and half but only in 1 teaspoon increments.
Cut out the center of each cupcake and reserve the removed cake. Spoon about a teaspoon of the ganache into each hole and replace the cut out cake. Don’t press down because you want your filling to remain in one place!
Fit a piping bag with your favorite tip, fill and frost!