Ingredients:

1 7/8 cup all purpose flour
1¼ cup sugar
2 teaspoons baking powder
¾ cup shortening
¾ cup milk
1 teaspoon vanilla
½ cup unbeaten egg whites (3 large)
3 tablespoons red fruit-flavored gelatin

remaining gelatin in package
¼ cup egg whites
1 cup sugar
1/8 teaspoon cream of tartar
¼ cup water

 Directions:

Sift together into bowl flour, sugar, baking powder and salt. Add shortening, milk and vanilla; beat for two minutes. Add egg whites and beat two more minutes. Pour into measuring cup, 1/3 cup of batter, then add gelatin, then pour over remaining cake batter in bowl. Using scraper, fold through batter just five times to swirl the colors. Pour into prepared pan or into two round layer pans 8" x 1½". Bake about 40 to 45 minutes in 350 degree oven.

Icing.
Use remainig gelatin in package, and combine in top of double boiler with egg whites, sugar, cream of tartar and water. Place ingredients over boiling water and beat until icing holds soft peaks (about 4 minutes by electric mixer on high speed, or about 10 minutes by rotary beater). Remove from boiling water and beat until peaks stiffen.