Preheat oven to 350°F. Line standard muffin pan with baking cups.
In medium bowl, combine flour and salt. In small heavy saucepan or microwave-safe bowl, melt butter and chocolate; stir until blended. In large bowl, combine chocolate mixture with sugar; mix well. Whisk in eggs and vanilla. Add flour mixture to chocolate mixture; mix until blended. If desired, stir in nuts. Distribute brownie mixture evenly into baking cups.
Bake 18-20 minutes or until toothpick inserted comes out clean. Cool cupcakes in pan on cooling rack for 5-8 minutes. Remove cupcakes from pan; cool completely.
Any of our cupcake recipes may be prepared in our Mini Tasty-Fill pans. Spray pans with vegetable pan spray, then fill each with about 1/2 cup batter. Place pans on cookie sheet and bake 14-16 minutes. Cool in pan on cooling grid for about 8 minutes; remove from pan and cool completely before filling and icing.