- Preheat the oven to 350 degrees. Line a twelve-count muffin tin with cupcake liners, and spray generously with nonstick cooking spray. Set aside.
- In a saucepan over low heat, melt the butter and 8 ounces of chocolate. Stir until smooth. Remove from heat, and set aside.
- In a large bowl, whisk together eggs and sugar. Add flour, cocoa, and baking soda. Stir in the melted chocolate until combined. Stir in remaining 3 ounces of chocolate and nuts if desired.
- Using a 2-ounce ice cream scoop, fill cupcake liners 3/4 full with batter. Bake until a firm crust forms on the cupcakes, about 20 minutes.
- Remove to a wire rack to cool, about 10 minutes. Remove cupcakes from pan, and continue to cool on a wire rack.
- Make frosting: Place chocolate morsels and cream in a heavy saucepan. Cook over low heat, stirring constantly with a rubber spatula, until combined and thickened, between 20 and 25 minutes.
- Increase the heat to medium low; cook, stirring, 3 minutes more. Remove pan from heat.
- Stir in corn syrup. Transfer frosting to a large metal bowl. Chill until cool enough to spread, about 2 hours, checking and stirring every 15 to 20 minutes.
- Ice cupcakes with a generous amount of chocolate frosting.
Brownie Cupcakes From Martha Stewart 6 Tablespoons unsalted butter 11 Ounces best-quality semi-sweet chocolate, coarsely chopped 3 large eggs 1 Cup sugar 3/4 Cup all-purpose flour 1/4 Cup unsweetened cocoa 1/8 Teaspoon baking soda 1 Cup coarsely chopped walnuts, (optional) Nonstick cooking spray For frosting: 24 Ounces semisweet chocolate morsels 4 Cups whipping cream 1 Teaspoon light corn syrup