Heavenly Banana-Nut Bars
["2/3 c. shortening", "1 1/2 c. sugar", "2 egg yolks", "1 c. mashed banana", "1 1/2 cake flour", "1 tsp. soda", "1/4 tsp. salt", "4 Tbsp. sour cream", "1/2 tsp. vanilla", "2 egg whites, beaten stiff", "1/2 c. chopped walnuts"]
["Cream sugar and shortening together, a little at a time.", "Add egg yolks and mix well.", "Add mashed banana.", "Sift flour with soda and salt.", "Add dry ingredients alternately with sour cream to creamed mixture.", "Mix thoroughly.", "Add vanilla; fold in well beaten egg whites and chopped nuts.", "Pour mixture into an 8 x 13-inch oblong pan that has been greased and floured lightly on the bottom.", "Bake in preheated 350\u00b0 oven for 45 minutes to an hour.", "Cool; cut in strips and roll in powdered sugar."]
["shortening", "sugar", "egg yolks", "banana", "cake flour", "soda", "salt", "sour cream", "vanilla", "egg whites", "walnuts"]