Instructions

• Preheat the oven to 350°F (176°C). Line two 12-cup muffin pans with liners (this recipe makes about 24 cupcakes). Set pans aside.
• In a large bowl, whisk the 3 large eggs with a fork until blended. Add 3/4 cup sour cream, 3/4 cup vegetable or canola oil, and 1 tablespoon vanilla extract; stir until completely combined.
• Add the 1 (13.25-ounce) box Super Moist Chocolate Fudge cake mix and the 1 (3.9-ounce) package instant chocolate pudding mix to the wet ingredients. Stir a few times just to moisten the dry ingredients.
• Pour in 1/2 cup hot water or coffee and mix until the batter is just combined. Do not overmix.
• Fold in 1 cup mini chocolate chips. If using a chocolate bar instead, chop it into pieces about the size of mini chips before folding in.
• Fill each cupcake liner about 3/4 full with batter.
• Bake one pan at a time for 18–23 minutes, or until a toothpick inserted in the center comes out clean or with a few moist crumbs and the tops spring back when lightly touched.
• Remove the pan from the oven and let the cupcakes cool in the pan for 5–10 minutes. Transfer the cupcakes to a wire rack and let them cool completely before frosting.
• For the frosting, place 20 tablespoons unsalted butter (room temperature) in the bowl of a stand mixer fitted with the paddle attachment (or use a handheld mixer). Beat on medium speed for 3–4 minutes, until the butter is pale and fluffy.
• With the mixer on low, add 3 cups powdered sugar, 3/4 cup Dutch-process cocoa powder, and 1/16 teaspoon salt. Mix on low until the dry ingredients are incorporated and no large dry streaks remain.
• Add 3 tablespoons heavy cream and 1 teaspoon vanilla extract. Increase the mixer to medium and beat until the frosting is smooth and spreadable, about 1–2 minutes.
• Transfer the frosting to a piping bag fitted with a star tip (or use a knife or spatula) and frost the completely cooled cupcakes.
• Cupcakes are best enjoyed within 1–3 days.