How to Make It
Preheat the oven to 400°F. Wrap the beets in bundles of 2 to 3 with 1/2 teaspoon salt, with aluminum foil and roast in the oven until they are easily pierced with a pairing knife, 1 to 1.25 hours. Unwrap the beets and let them cool to warm. Peel and discard the skins from the beets and cut into 1-inch slices. Place the beets in a serving bowl and sprinkle with salt and pepper. Drizzle the dressing over the beets, then scatter the walnuts and dill over the salad. Serve.
In a bowl, whisk together the vinegar, shallot, 1/2 teaspoon salt and 1/4 teaspoon pepper and let stand 5 minutes. Whisk in the mayonnaise.