Grease a 9"e square pan. Preheat oven to 350F. Sift flour, baking powder, and salt together. Melt butter and chocolate together over low heat. Beat eggs and sugar until light. Add flour mixture, chocolate mixture and 1/4 cup Kahlua. Blend well. Stir in nuts. Bake 30 minutes or until done. Cool in pan. Brush with remaining Kahlua.