Instructions

• Preheat the oven to 350°F (176°C). Line two muffin pans with liners (this recipe yields about 24 cupcakes). Set pans aside.
• In a large bowl, whisk the 3 large eggs until combined. Add 3/4 cup sour cream, 3/4 cup vegetable or canola oil, and 1 tablespoon vanilla extract; stir until smooth.
• 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 to moisten the dry mix.
• Add 1/2 cup hot water or hot coffee and mix just until combined. Do not overmix.
• Fold in 1 cup mini chocolate chips (or chopped chocolate cut to about the size of mini chips if using a chocolate bar).
• Fill each cupcake liner about 3/4 full. Bake one tray 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.
• Let the cupcakes cool in the pan for 5–10 minutes, then transfer them to a wire rack to cool completely before frosting.
• To make the frosting: in a medium bowl with a handheld mixer or in a stand mixer fitted with the paddle attachment, beat the 20 tablespoons unsalted butter at medium speed for 3–4 minutes until pale and creamy.
• Add the 3 cups powdered sugar and the 3/4 cup Dutch‑process cocoa powder in 2–3 additions, mixing on low after each addition until incorporated to avoid a sugar cloud; then increase to medium speed and beat until mostly smooth.
• Add 2 tablespoons of the 3 tablespoons heavy cream, the 1 teaspoon vanilla extract, and the 1/16 teaspoon salt. Beat on medium‑high until the frosting is smooth and fluffy, about 1–2 minutes.
• If the frosting is still too thick to pipe, add the remaining 1 tablespoon heavy cream and beat briefly to combine. If the frosting is too thin, chill it 10–20 minutes to firm before piping.
• Transfer the frosting to a piping bag fitted with a star tip (or use a spatula) and frost the completely cooled cupcakes. Store and enjoy within 1–3 days.