This recipe is part of a memorable spring brunch menu.
Bring another small pot of water to a boil, and prepare an ice-water bath in a large bowl. Wash and trim the asparagus by cutting off the tough lower half. Cut remaining stalks into 1-inch pieces, and set aside. Wash snap peas and trim ends, removing any strings. Cut into thirds. When the water boils, add 1 teaspoon salt, asparagus, snap peas and carrots. Cook until the asparagus and peas turn bright green, 30 seconds to 1 minute. Drain them in a colander, rinse with cold water, and dunk into the ice bath. Let sit until vegetables are cool. Drain the vegetables well, blot them with paper towels, and set aside.
Pour out the hot cooking liquid from the beets and add cold water. When the beets are cool enough to handle, rub the skins off with your hands (under water), then cut them into quarters. If using larger beets, cut them into 1/2-inch pieces. Set aside.
Zest lemon and set zest aside. In a small bowl, whisk together mustard, lemon juice, and a pinch of salt and pepper. Slowly drizzle in the oil while continuing to whisk until the dressing is emulsified. Adjust seasoning.
In a large serving bowl, arrange the vegetables in sections or rows. Drizzle with the dressing and sprinkle the lemon zest (to taste) over the top. When ready to serve, toss all of the ingredients together.