Revised version of the Brown Derby Grapefruit Cake recipe served at Disney. You can substitute fresh grapefruit for the canned and leave out the food coloring (I actually forgot it!) if desired.
If you have a kitchen scale you can skip sifting the flour and just weigh out 5.25 oz. If you don't have a scale and are using cups, it's important to sift so that the flour will be well-aerated and your 1 1/2 cups of flour will be nice and light.
The original frosting called for 12 oz of cream cheese, 3/4 cup of sugar and less grapefruit zest and juice. I used the original amounts but just barely had enough frosting and recommend going with 16 oz of cream cheese, 1 cup sugar, etc. etc. as written so that you'll have plenty of frosting.