Instructions

• Preheat the oven to 350°F (175°C). Line a standard 12-cup muffin tin with paper liners.
• In a large bowl, whisk or beat together 2 eggs, 3/4 cup buttermilk, 1/4 cup plain Greek yogurt, 1/2 cup canola oil, and 1 tablespoon vanilla extract until smooth.
• In a separate bowl, whisk together 1 1/2 cups all-purpose flour, 1 1/2 cups granulated sugar, 1 cup unsweetened cocoa powder, 1 1/2 teaspoons baking soda, 1 1/2 teaspoons baking powder, and 1 teaspoon kosher salt.
• Add the dry ingredients to the wet ingredients and mix on low speed or fold with a spatula until no visible flour remains and the batter is smooth. Do not overmix.
• Stir in 1/3 cup hot black coffee until combined. The batter should be pourable but not very thin. Fold in 1/2 cup mini semi-sweet chocolate chips, if using.
• Divide the batter evenly among the prepared liners, filling each about two-thirds full.
• Bake at 350°F for 15–18 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs. Remove the pan from the oven.
• Let the cupcakes cool in the pan for 5–10 minutes, then transfer them to a wire rack and cool completely before frosting.
• For the frosting: In a large bowl, beat 3 sticks (1 1/2 cups) room-temperature salted butter until creamy.
• Add 3 cups powdered sugar and beat on low until incorporated, then increase speed and beat until the mixture is light and fluffy, about 2 minutes.
• Add 3/4 cup unsweetened cocoa powder and 2 teaspoons vanilla extract. Beat, scraping down the sides of the bowl as needed, until the frosting is uniform in color with no streaks, about 2 minutes.
• Add 3 tablespoons heavy whipping cream and whip the frosting for 2–4 minutes until light and fluffy. If the frosting is too thick, add the remaining 1 tablespoon heavy cream (for a total of 3–4 tablespoons) and beat until you reach the desired consistency.
• Frost the cooled cupcakes as desired. Store frosted cupcakes covered in the refrigerator for 3–4 days and bring to room temperature before serving.