Butterscotch Bliss Bars

2 cups sifted all-purpose flour
1 teaspoon baking powder
1/4 teaspoon baking soda
1 teaspoon salt
1 cup chopped walnuts (optional)
2/3 cup butter
2 cups packed brown sugar
2 eggs
2 tablespoons vanilla extract
1 cup semisweet chocolate chips
1/2 cup butterscotch chips (optional but heavenly - if you omit add 1/2 cup more chocolate chips)

Directions
Preheat oven to 350 degrees F (180 degrees C).
Measure 2 cup sifted flour. Add baking powder, baking soda, and salt. Sift again. Add 1/2 cup chopped nuts. Mix well and set aside.
Melt 2/3 cup butter. Add 2 cup firmly packed brown sugar and mix well. If shortening is used, add 1 tablespoon hot water. Cool slightly.
Add eggs already beaten and vanilla. Blend well. Then add flour mixture, a little at a time, until well mixed. mix the chocolate chips and the butterscotch chips into the batter.
Spread in 9 x 13 inch pan. Bake for 45 minutes.