Grease bottom and sides of 9 x 13 inch pan.

1 c. (6 oz. pkg.) butterscotch pieces
1/2 c. butter

Melt in 3-quart saucepan over medium heat, stirring constantly, remove from heat, cool to lukewarm.

1 1/2 c. flour
2/3 c. firmly packed brown sugar
2 tsp. baking powder
1/2 tsp. salt
1 tsp. vanilla
2 eggs

Add to butterscotch mixture in saucepan. Mix well.

2 c. miniature marshmallows
2 c. (12 oz. pkg.) semi-sweet chocolate pieces
1/2 c. chopped nuts

Fold into butterscotch mixture just until combined, about five strokes. Spread in prepared pan. Bake at 350 degrees for 20-25 minutes. DO NOT OVERBAKE. Center will be jiggly but becomes firm upon cooling.