1/2 c. peanut butter
1/3 c. butter
3/4 c. brown sugar
3/4 c. sugar
2 eggs
2 tsp. vanilla
1 c. flour
1 tsp. baking powder
1/2 tsp. salt

Grease 9x13 pan. Top with 12 ounces chocolate chips. Pull knife through to marbelize after 5 minutes. Bake 15-25 minutes or until light brown.