Simple yet gorgeous, this spring salad of roasted beets and tender lettuces really pops thanks to the addition of Pickled Rhubarb.
Preheat oven to 400°F. Scrub beets, then place on a piece of parchment-lined foil. Drizzle with 1 tablespoon oil; season with salt and pepper. Wrap in foil and roast until fork-tender, about 1 hour. Let stand until cool enough to handle. Rub off skins and discard. Halve beets and cut into 1/2-inch wedges (you should have 1 1/2 cups).
Whisk pickling liquid into mustard, then gradually whisk in remaining 4 tablespoons oil and dill; season to taste. Toss lettuce, beets, and pickled rhubarb with 2 to 3 tablespoons dressing; season to taste. Serve, sprinkled with more herbs and drizzled with more dressing.