Preheat oven to 375 degrees.
In a large saucepan combine butter and chocolate.
Stir occasionally over low heat until melted and smooth.
Mix flour with 2 T cocoa.
In a large bowl beat egg whites with a mixer on high speed until foamy.
Gradually beat in sugar, then beat until whites hold stiff, shiny peaks.
Stir liqueur, vanilla, flour mixture, and egg yolks into chocolate butter mixture.
Stir in about 1/4 of the egg whites.
Fold remaining whites into chocolate mixture; there should be no streaks.
Spoon batter equally into 8 buttered ramekins.
Bake cakes just until edges feel firm but centers are still soft when gently pressed, 11 - 12 minutes.
Let cool 5 minutes.
Invert and serve with chocolate sauce and ice cream.