Preheat oven to 400°F. Scrub beets; pierce with a fork and place in a small baking dish. Cover with a snug lid or wrap tightly with aluminum foil. Bake until fork-tender, 45 to 60 minutes. Remove from oven and let cool.
While beets roast, make chimichurri: In a small bowl, combine oil, vinegar, shallot, parsley, oregano, salt and crushed red pepper flakes. Whisk thoroughly.
Remove skins from beets. Slice beets crosswise 1/2 inch thick. Carefully toss slices with chimichurri. Serve immediately.
Recipe adapted with permission from Vibrant Food, written and photographed by Kimberley Hasselbrink (Ten Speed Press, copyright 2014).