Chess Squares

• 2 Sticks Butter
• 2 1/4 cup dark brown sugar
• 1 cup white sugar
• 4 egg yolks
• 2 cups flour
• 2 teaspoon baking powder
• 1/4 teaspoon salt
• 1 cup chopped nuts
• 1 1/2 teaspoons vanilla
• 4 egg whites
• Powdered sugar

Blend melted butter and sugar. Add egg yolks and beat well. Sift flour, baking powder and salt together; add to creamed mixture. Fold in nuts and vanilla. Beat egg whites until stiff; fold into creamed mixture. Batter will be very thick. Spread batter in greased 9"x13" pan and bake  at 350 degrees for 35 minutes. When done sprinkle with powdered sugar.