Grandma's Blondies

2/3 cup butter, melted
2 cups brown sugar
2 eggs
2 tsp. vanilla
2 cups flour
1 tsp baking powder
1/4 tsp. baking soda
1 tsp salt
1/2 cup chopped walnuts
1 cup chocolate chips

Mix melted butter and brown sugar. Add vanilla and eggs, mix well. Add dry ingredients. Toss walnuts and chocolate chips with 1 TBS flour and fold into batter. Spread into a greased cake pan and bake at 350 for 25-30 minutes.