Instructions

• Make the chocolate base for the frosting: place 2 ounces semi-sweet chocolate and ½ cup heavy cream in a small saucepan over low heat. Stir constantly until the chocolate is fully dissolved and the mixture is smooth. Do not let the cream boil; heat just enough to melt the chocolate.
• Remove the pan from the heat and let the chocolate-cream mixture cool to room temperature. Transfer it to a mixing bowl, cover, and chill in the refrigerator for at least 8 hours (or overnight).
• When ready to finish the frosting, whip the chilled chocolate-cream mixture with an electric mixer on medium-high speed until thick and firm and it holds its shape. Set the whipped mousse frosting aside in the refrigerator until ready to use.
• Preheat the oven to 350°F. Line a mini cupcake pan with 20 liners.
• In a medium bowl, whisk together ½ cup all-purpose flour, ¼ teaspoon baking soda, ½ teaspoon baking powder, and ⅛ teaspoon salt. Set this dry mixture aside.
• In a separate small bowl, whisk ¼ cup boiling water with 2 ½ tablespoons unsweetened cocoa powder and ¼ teaspoon instant espresso powder until fully dissolved. Set this cocoa-espresso mixture aside.
• In a mixing bowl, beat 4 tablespoons unsalted butter (softened) and ⅓ cup granulated sugar together until well combined and light in texture.
• Add ¼ teaspoon vanilla extract and 1 large egg to the butter-sugar mixture and continue beating until the mixture is smooth and creamy.
• Add the dry flour mixture to the wet mixture and beat just until combined.
• Add the cocoa-espresso mixture to the batter and beat until the batter is smooth and evenly combined.
• Fill each mini cupcake liner with about 1 tablespoon of batter (about 2/3 full).
• Bake the mini cupcakes for 10 to 15 minutes, or until a toothpick inserted in the center comes out clean.
• Remove the cupcakes from the oven and let them cool completely before frosting.
• Once cupcakes are fully cool, pipe or spread the whipped chocolate mousse frosting onto each cupcake.