This ad from the Feb. 1952 issue of Better Living promotes the idea of flavoring and coloring your cake with fruit flavored gelatin, "Your cake will have a wonderful, tempting fruit flavor."
When this ad came out there were only three flavors of Betty Crocker Cake Mixes. The colorvision cake called for the Party Cake mix that made a yellow cake. To make it you added three tablespoons of your favorite fruit flavored gelatin as you started to mix the cake.
To make the Icing : Mix, in top of double boiler all the remaining fruit gelatin in package, 1/4 cup egg whites, 1 cup sugar,1/8 tsp. cream of tartar, 1/4 cup water. Place over boiling water and beat with electric mixer on high speed, or rotary beater, until icing holds stiff peaks. remove from over boiling water and beat about 1 min. longer.
I don't recall seeing this idea in later Betty Crocker booklets so I wonder if it really turned out very well. It seems like it would work. Remember the gelatin poke cakes? You don't hear about them much any more either. Maybe this idea just came and went.