Cream butter in bowl. Melt chocolate in double boiler. Blend into butter with 2 cups sugar. Beat in eggs, one at a time. Add vanilla. Sift flour, baking powder and salt together; add to chocolate mixture. Chill dough 2 hours. Form into balls; roll in rest of sugar. Place 5 cm apart on ungreased cookie sheet; bake 10 minutes at 350 degrees. Don't overbake; cookie should be chewy. Makes 50 cookies. Formatted by Mary Wilson, BWVB02B. ----