How to Make It
In a small saucepan, combine the shallot and vinegar and let stand for 10 minutes. Whisk in the olive oil and season with salt and pepper.
Meanwhile, using a very sharp knife, peel the grapefruits, oranges and tangerine, being sure to remove all of
the bitter white pith. Working over a large bowl to catch the juices, cut the navel orange and tangerine in between the membranes to release the sections. Slice the grapefruits and blood oranges into rounds, then cut into quarters. Arrange the endives and the citrus on a large platter.
Bring the dressing to a simmer over moderate heat. Remove from the heat and add the bacon. Drizzle the dressing over the salad and top with the tarragon and mesclun, if using.