4 oz. unsweetened chocolate
6 tbsp. butter
2 c. (12 oz.) semi-sweet chocolate chips, divided
1/2 c. flour
2 tbsp. unsweetened cocoa powder
1/4 tsp. baking powder
1/4 tsp. salt
1 c. sugar
3 eggs
1 1/2 tsp. vanilla extract

Heat oven to 350 degrees. Chop unsweetened chocolate. Cut butter into pieces. Melt chopped chocolate, butter, and 1 cup chocolate chips in a small pan in oven, stirring occasionally. Cool.

Combine flour, cocoa, baking powder, and salt. Beat sugar and eggs about 2 minutes. Beat in vanilla. Stir in chocolate mixture, then flour mixture, and finally, the remaining 1 cup chocolate chips. Cover and chill until firm, at least 1 hour. Heat oven to 350 degrees. Shape into 1-inch balls. Bake on ungreased cookie sheets, 2 inches apart, until puffed, about 10 minutes.