1 (6 oz.) pkg. semi-sweet chocolate chips
1/2 c. butter
1 1/2 c. flour
1 c. sugar
1/2 tsp. baking powder
1/2 tsp. vanilla
2 eggs
2 c. chopped nuts
2 c. miniature marshmallows

Heat 1/2 cup of the chocolate chips and the butter over low heat until melted. Cool. Heat oven to 375 degrees. Mix flour, sugar, baking powder, vanilla, eggs, and chocolate mixture. Spread in ungreased 9 x 9 inch pan. Bake 15 minutes. Sprinkle with marshmallows, nuts, and remaining chips. Bake until marshmallows are golden brown and wooden pick comes out clean when inserted in center, about 15-20 minutes. Cool completely.