Yellow Cake and Caramel Icing

YELLOW CAKE: Cream butter and sugar. Add egg yolks one at a time. Sift flour and baking powder together, then add salt. Add flour mixture and milk alternately. Add vanilla. Beat egg whites until stiff. Fold into batter. Bake in preheated 350 degree oven for about 35 minutes. Makes 2 large or 3 small layers. CARAMEL ICING: Mix 1 1/2 cups sugar, milk, butter and salt and bring to a boil. Melt 1/2 cup sugar in small heavy frying pan stirring constantly. When melted, add to boiling mixture. Stir until candy thermometer rises to soft boil. Remove from heat and beat until slightly cool. Will make enough for filling and icing.