Preheat the oven to 350°F (177°C). Line a 12-count muffin pan with cupcake liners. This recipe yields 14–15 cupcakes, so line a second muffin pan with 2 or 3 more liners (or bake in batches).

In a medium bowl, whisk together the flour, cocoa powder, baking powder, baking soda, and salt. Set aside.

In a large bowl, preferably with a pour spout, whisk together the sugar, buttermilk, oil, egg, vanilla, and vinegar until combined. Pour the dry ingredients into the wet ingredients, add the hot coffee, and whisk until the batter is completely combined. The batter will be thin.

Pour the batter into the liners, filling only 2/3 to 3/4 full to avoid overflowing and sinking.

Bake for 20–22 minutes, or until a toothpick inserted in the center comes out clean. Another way to test for doneness is to lightly press your finger into the surface of the warm cupcake. If the cupcake bounces back, they’re done. If your finger leaves an imprint, they need more bake time.

Allow cupcakes to cool in the pan for 10–20 minutes, and then transfer to a cooling rack to cool completely before frosting.

With a handheld or stand mixer fitted with a paddle attachment, beat the butter on medium speed until creamy, about 2 minutes. Add confectioners’ sugar, cocoa powder, 1/4 cup (60g/ml) of the cream, vanilla, and salt. Beat on low speed for 30 seconds, then increase to high speed and beat for 1 full minute. If the frosting seems too thick, beat in another Tablespoon of cream.

Frost cooled cupcakes and top with sprinkles, if desired. You can swipe the frosting on with an icing knife or use a piping tip such as Ateco 826. For cat cupcakes, see recipe Note.

Store cupcakes at room temperature for up to 2 days or in the refrigerator for up to 4 days. I recommend a cupcake carrier for storing and transporting decorated cupcakes.