Recipe by Ina Garten
1 tablespoon Dijon mustard
1 1/2 teaspoons kosher salt
1/2 cup good olive oil
4 ripe Hass avocados
2 large red grapefruits
Place the mustard, lemon juice, salt, and pepper in a small bowl. Slowly whisk in the olive oil until the vinaigrette is emulsified.
Before serving, cut the avocados in 1/2, remove the seeds, and carefully peel off the skin. Cut each half into 4 thick slices. Toss the avocado slices in the vinagrette to prevent them from turning brown. Use a large, sharp knife to slice the peel off the grapefruits (be sure to remove all the white pith), then cut between the membranes to release the grapefruit segments.
Arrange the avocado slices around the edge of a large platter. Arrange the grapefruit segments in the center as well as in between each slice of avocado. Spoon the vinaigrette on top, sprinkle with salt and pepper, and serve.