Congo Squares

My Grandma GG always had these ready for us kids when we would come visit.  Making them reminds me of all the summers we'd go to Utah to see grandma.

2 1/4 c brown sugar
2/3 c softened butter
3 eggs
2 3/4 c flour
1 1/2 tsp baking powder
1 tsp vanilla
1 pk chocolate chips
1 c nuts (optional)

Add butter to sugar and cream well. Add eggs and beat. Add rest of ingredients. Mix well and spread in pan 3/4 inch thick. Bake at 350 degrees for 20 minutes. Cool and cut.