Slice ends off grapefruits and stand upright on a counter. Cut away skin and membrane, exposing fruit. Working over a bowl to catch the juice, separate sections by slicing with a serrated knife between membranes. Remove and discard the seeds. Slice avocado halves lengthwise in 1/2-inch slices. Arrange alternating grapefruit sections and avocados slices on 6 salad plates.
Whisk together sour cream, lime juice, honey, salt, and pepper in a small bowl. Just before serving, spoon about 2 tablespoons dressing in a stripe over each salad. Garnish with mint leaves and serve
Variations: Toss chunks of avocado and supremes of grapefruit with salt, pepper, and olive oil.
c.1996, M.S. Milliken & S. Feniger, all rights reserved