I found this recipe in my "PUT THE UN IN COOKING FUN WITH 7UP, cookbook. This little booklet was made by the Seven-Up Company in 1969. I used a white cake mix for this cake and cherry juice in place of the vanilla, then I drizzled some juice down the cake and topped with cherries. I had a 10 ounce jar of cherries so I was able to do more with the juice.
For cake, drain cherries and reserve cherries for top of cake. Add enough 7up to cherry juice to make 1 2/3 cups liquid. In large mixing bowl add eggs and 7up mixture to cake mix. Beat at medium speed for 4 minutes. Bake in two well greased 8 inch cake pans for 35-40 minutes. Cool 10 minutes, invert on rack. When cake is completely cool frost with 7up frosting.
For frosting, Put first 5 ingredients in top of double boiler over boiling water. Beat wit electric mixer on high speed till mixture forms peaks (about 7 minutes). Remove from heat add juice or vanilla and beat for 1 minute. Frost cake