Spinach and Quinoa Salad with Grapefruit and Avocado

baby spinach

ruby red grapefruits, peeled and fruit separated, reserving 3 slices

haas avocados, diced

cooked quinoa (1/3 cup dry)

olive oil

champagne vinegar

chopped shallots

salt and pepper

grapefruit juice from 3 reserved slices of grapefruit