1. Preheat the oven to 350 degrees F. Spray Coffee Mugs with baking spray (Pam with Flour). Or line muffin tins with paper liners
2. Sift the flour, sugar, cocoa, baking soda, baking powder, and salt into the bowl of an electric mixer fitted with a paddle attachment and mix on low speed until combined.
3. In another bowl, combine the buttermilk, oil, eggs, and Kahlua. With the mixer on low speed, slowly add the wet ingredients to the dry. Add the 1 ½ teaspoons of espresso granules to the cup of hot coffee and stir to combine. With mixer still on low, add in the coffee/espresso mixture and stir just to combine, scraping the bottom of the bowl with a rubber spatula.
4. Using a large scoop (about 3 tablespoons), distribute the batter into the prepared muffin tins. For coffee mugs, fill about 2/3rd full
5. Bake for 18-22 minutes, or until a cake tester comes out clean. Larger coffee mugs may take longer, so test after 18 minutes ”“ if the toothpick comes out wet, bake for an additional 5 minutes and test again. Cool in the pans for 15 minutes, then remove them onto a cooling rack and cool completely.
6. When completely cool, brush the tops of cupcakes with Kahlua.