Make Cupcakes: Preheat oven to 350°F (175°C) and line 2 cupcake pans with cupcake liners. In a large bowl, whisk together the cake mix, eggs, oil, coffee, and Kahlúa until thoroughly combined.

Fill Liners: Fill each cupcake liner about ¾ full with batter.

Bake: Bake until a toothpick inserted into the middle of each cupcake comes out clean, about 25 minutes.

Cool: Let the cupcakes cool completely in the muffin tins.

Make Ganache Filling: Meanwhile, make the ganache filling. Place the chocolate chips in a medium heat-safe bowl. In a small saucepan over medium heat, heat the heavy cream until it just begins to bubble. Pour the hot cream over the chocolate chips and let it sit for 5 minutes. Add the Kahlúa and a pinch of salt. Whisk until smooth.

Refrigerate Ganache: Refrigerate the ganache while you make the frosting. This will allow it to thicken slightly.

Make Frosting: In a large bowl using a hand mixer, beat the softened butter until light and fluffy. Add about half of the powdered sugar, the cocoa powder, and a pinch of salt. Beat until no lumps remain. Add the heavy cream, Kahlúa, and vanilla extract. Beat until smooth. Then, add the remaining powdered sugar and beat until combined. Transfer the frosting to a large piping bag fitted with a large, open-star tip.

Fill Cupcakes: Scoop out a heaping teaspoon from the center of each cooled cupcake to create a well. Spoon the Kahlúa ganache into the cupcake wells.

Frost and Decorate: Pipe the frosting on top of the filled cupcakes and garnish with chocolate and gold sprinkles.