Heat oven to 350 degrees F. Line a 12-count muffin tin with cupcake liners, and spray generously with cooking spray; set aside.
In a saucepan over low heat, melt the butter and 8 ounces of the chocolate. Stir until smooth. Remove from heat, and set aside.
In a large bowl, whisk together the eggs and sugar. Add the flour, cocoa, and baking soda. Stir in the melted chocolate until combined. Stir in the remaining 3 ounces of chocolate and nuts, if desired.
Using a 2-ounce ice cream scoop, fill each cupcake liner 3/4 full with batter. Bake until a firm crust forms on the cupcakes, about 20 minutes. Remove to a wire rack to cool 10 minutes. Remove cupcakes from pan, and continue to cool on a wire rack.
Ice cupcakes with a generous amount of 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. Use immediately.
Yield: 6 cups
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