2/3 c. butter
1 3/4 c. sugar
2 eggs
3 c. sifted cake flour
1/2 tsp. salt
2 1/2 tsp. baking powder
1/2 c. grapefruit juice
3/4 c. milk
1 tsp. grated grapefruit rind
1 1/2 tsp. vanilla extract

Cream butter; gradually add sugar, beating well. Add eggs, one at a time, beating well after each addition. Combine flour, baking powder, and salt; add to creamed mixture. Alternate with grapefruit juice, beginning and ending with flour mixture. Gradually add milk. Stir in grapefruit rind and vanilla extract; mix well. Pour batter into 2 greased and floured 9 inch round cake pans. Bake at 350 degrees for 25 minutes. Cool in pans for 10 minutes; remove from pans. Cool completely on wire rack. Spread frosting between layer and on top and sides of cake. Yields 1 (2 layer) cake.

GRAPEFRUIT FROSTING:

1 1/2 c. sugar
2 egg whites
1 tbsp. light corn syrup
1/8 tsp. salt
1/3 c. grapefruit juice
1 tbsp. grated grapefruit rind
2 tsp. vanilla

Combine first 5 ingredients in top of double boiler. Beat at low speed of an electric mixer for 30 seconds or just until mixed. Place over boiling water; beat constantly at high speed for 7 minutes or until stiff peaks are formed. Remove from heat. Add grapefruit rind and vanilla; heat 1 or 2 minutes or until frosting is thick enough to spread. Yields 3 3/4 cups or enough for a 2 layer cake.