Preheat oven to 350F. Combine oil and sugar, beat until smooth, add egg yolks, mix thoroughly. Add hot water, then dry ingredients which has been sifted together. Stir in potatoes, nuts, and vanilla. Fold in stiffly beaten egg white. Bake in Three 8 inch cake pans.
To make icing, mix all ingredients together except coconut. Cook over medium heat about 12 minutes or until thick. Remove from heat and beat until cool enough to spread. Add coconut.
Cajun Country -- New Iberia, Louisiana