Sift together the flour, baking powder and salt; set aside. Mix vanilla with butter or margarine. Gradually blend in sugar.
Beat in 1 egg yolk.
Add flour mixture alternately with milk.
Beat 4 of the egg whites until they stand in soft, stiff peaks.
Fold into mixture. Divide batter into 2 equal parts and blend 4 egg yolks and yellow food coloring into 1 part. Drop white and yellow batters alternately into well-greased, lightly floured 10 x 4-inch tube pan.
Bake in preheated oven at 325 degrees for 1 hour and 20 minutes or until cak e tester inserted in center comes out clean.
Remove from oven.
Cool in pan 20 minutes.
Turn out onto cake rack to finish cooling.
Frost top and sides with Easy Vanilla Frosting.
Easy Vanilla Frosting: Place all ingredients in small deep bowl of electric mixer.