Peel the beets and the shallot. Combine them in the bowl of a food processor fitted with a metal blade, and pulse carefully until the beets are shredded; do not puree. (Or grate the beets by hand and mince the shallots; combine.) Scrape into a bowl.
Toss with the salt, pepper, mustard, oil, and vinegar. Taste and adjust the seasoning. Toss in the herbs and serve.
Recipe courtesy of Mark Bittman's THE MINIMALIST COOKS DINNER (Broadway, 2001)