1. Preheat the oven to 350°F (175°C). Line a 12-cup muffin pan with paper cupcake liners and set aside.

2. In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, unsweetened cocoa powder, black cocoa powder, baking soda, baking powder, fine sea salt, and instant espresso powder until well combined and no streaks of cocoa remain.

3. Add the buttermilk, vegetable oil, large egg, and vanilla extract to the dry ingredients. Whisk or mix on low speed just until the batter looks mostly smooth and combined, without overmixing.

4. Pour in the hot brewed coffee or hot water and whisk again until the batter becomes smooth and fairly thin. Scrape the sides and bottom of the bowl to make sure everything is evenly incorporated.

5. Divide the batter evenly among the 12 cupcake liners, filling each about two-thirds full. Bake for 18 to 20 minutes, or until the tops spring back lightly when touched and a toothpick inserted in the center comes out with a few moist crumbs.

6. Let the cupcakes cool in the pan for 5 minutes, then transfer them to a wire rack to cool completely before frosting.

7. While the cupcakes cool, make the vanilla buttercream. In a large bowl, beat the softened unsalted butter with a hand mixer or stand mixer until pale and creamy, about 2 minutes.

8. Gradually add the powdered sugar, mixing on low speed at first to avoid clouds of sugar, then increasing to medium speed until the frosting is thick and fluffy.

9. Beat in the vanilla extract, heavy cream or milk, and fine sea salt. Continue mixing for 1 to 2 minutes until the frosting is smooth, light, and pipeable. If needed, add a tiny splash of extra cream or an extra spoonful of powdered sugar to adjust the consistency.

10. To make the ganache, place the semisweet chocolate chips and heavy cream in a small heatproof bowl. Warm in the microwave in 15-second bursts, stirring between each, until the chocolate is melted and the mixture is smooth. Stir in the light corn syrup if using for extra shine. Let the ganache cool for several minutes until slightly thickened but still pourable.

11. Transfer the vanilla buttercream to a piping bag fitted with a large star tip. Pipe tall swirls of frosting onto each cooled cupcake.

12. Drizzle the cooled ganache over the frosting on each cupcake, letting it run slightly down the sides of the swirls.

13. Immediately sprinkle the tops with mini chocolate chips, chocolate cookie crumbs, and festive sprinkles. Allow the ganache to set for a few minutes, then serve and enjoy.