Preheat oven to 325 degrees. Sift together dry ingredients then add egg yolks, oil, water, zest, and vanilla and mix well. When incorporated, fold in egg whites. Bake for 1 hour. When cake is cooled, slice in half and frost in between layers, on top and around sides.
Beat cream cheese with lemon juice until fluffy. Mash 6 grapefruit sections into small pieces. Add sugar to cheese mixture along with food coloring, fruit zest and blend will. Add remaining grapefruit.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.