Grapefruit and avocado are one of those natural food pairings, like lamb and mint, or dark chocolate and raspberries. They just taste good together. They are perfect for a summer salad when avocados are relatively cheap and the grapefruit from our tree are finally ripe. My mother uses homemade plum jam to make a sweet mayo dressing for this simple salad. We usually serve it on some lettuce, but I forgot to this time, and it isn’t really necessary.
Arrange slices of avocados and grapefruit segments on a plate, either on lettuce or not. In a small bowl, mix mayonnaise together with jam and lemon juice, taste test for the balance between the sweet of the jam and the sour of the lemon and make any adjustments needed. Spoon dressing over salad. Salt and pepper to taste.
The hardest part of making the salad is segmenting the grapefruit. Helen of Beyond Salmon shows in detail the steps to segment an orange which is almost identical to how I segment grapefruit. Grapefruit are somewhat bigger than oranges. After getting the peel off, I cut them in half along the line of a membrane and then just work with half a grapefruit at a time.