1 pkg. (18.5 oz.) yellow cake mix
1/8 tsp. baking soda
1 c. mashed banana (2 to 3 med.)
1/2 c. finely chopped nuts (optional)

Heat oven to 350 degrees. Grease and flour oblong pan, 13 x 9 x 2 inches. Prepare cake mix as directed on package except - stir soda into dry mix; use 1 cup plus 4 tablespoons water and add banana. Fold in nuts. Pour batter into pan.

Bake until pick inserted in center comes out clean, 35 to 40 minutes.