- 1 cup finely grated peeled fresh horseradish (1/2 lb; use small teardrop-shaped holes of a box grater)
- 3 cooked medium beets (reserved from pickled quail eggs , peeled and coarsely chopped (1 3/4 cups)
- 1/2 teaspoon salt
- 1/2 teaspoon sugar
- 1/4 cup cider vinegar
- Coarsely purée all ingredients in a food processor, scraping down side of bowl as needed, 30 to 40 seconds. Let stand, covered, at room temperature at least 1 hour (for flavors to develop).