Squirrel Bars

From "Favorites" Cookbook

1/2 cup peanut butter
1/3 cup butter
3/4 cup brown sugar
3/4 cup sugar
2 eggs
2 tsp vanilla
1 cup flour
1 tsp baking powder
6 ounces chocolate chips

Mix together first four ingredients.  Add eggs and vanilla.  Stir in flour and baking powder.  Spread mixture in a greased 9"x13" pan.  Sprinkle chips on top.  Bake 3 minutes at 350 degrees.  Take out and "marbelize."  Return to oven for another 18 to 20 minutes.  Cook and cut into bars to serve.