These get better with time, so don’t hesitate to make them ahead.
- 1 pound baby yellow or red beets, trimmed, scrubbed
- ½ cup Sherry or red wine vinegar, divided
- 2 tablespoons plus ¼ cup olive oil
- 1 medium shallot, finely chopped
- 1 teaspoon chopped fresh thyme
- ¼ cup raw pistachios, chopped
- 2 tablespoons coarsely chopped fresh tarragon
Preheat oven to 425°. Combine beets, ¼ cup vinegar, 2 Tbsp. oil, and ¼ cup water in a baking dish; season with salt. Cover with foil and steam until beets are tender, 40–50 minutes. Let cool slightly. Rub off skins with paper towels; cut beets into quarters (or ½” wedges if larger).
Toss beets with shallot, thyme, remaining ¼ cup vinegar, and remaining ¼ cup oil in a large bowl; season with salt. Let sit at least 2 hours.
Toss with pistachios and tarragon just before serving.
DO AHEAD: Beets can be marinated 2 days ahead. Cover and chill.