Preheat oven to 375°F. In large mixing bowl, beat together butter and sugar with mixer until light and fluffy. Add eggs and vanilla; mix well. Blend in chocolate. Combine flour and baking powder; gradually add to butter mixture, beating until smooth. Cover and chill until firm, about 1 hour. Roll dough approximately 1/8 in. thick. Dip cutters in flour, cut and transfer cookies to cookie sheet. Bake 8-10 minutes. Remove to rack and cool thoroughly. Recipe may be doubled.