Spray inside 6 individual soufflé dishes or custard cups with nonstick cooking spray; set aside. In small heavy saucepan over low heat, melt chocolate, stirring until smooth. Add butter and sugar; stir until melted.
Pour chocolate mixture into large bowl. In small bowl, mix together flour, cocoa, and baking powder.
With electric mixer at medium-high speed, beat chocolate mixture; add eggs and flour mixture; beat about 6 minutes until thickened. Divide mixture evenly among prepared dishes; cover with plastic wrap. Freeze at least 2 hours or overnight.
Heat oven to 375° F.
Remove and discard plastic from frozen cakes. Bake 15 to 18 minutes, until edges are set and center is moist. Cool cakes slightly before inverting onto serving platters.Makes 6 Source: