This unusual vinaigrette is delicious with grilled, roasted, or sautéed fish or sea scallops, braised leeks, sliced warm new potatoes, roasted onions, and buckwheat noodles. Because the vinaigrette has a vivid purple color that stains food quickly, I prefer to spoon the vinaigrette onto the plates and place the food on top of it.

• 1-1/2 pounds (3 to 4) medium beets, peeled and cut into 1-inch cubes
• 2 tablespoons balsamic vinegar
• 2 tablespoons roasted walnut oil, extra-virgin olive oil, or Asian sesame oil
• Fresh lemon or lime juice, to taste
• Pinch of kosher salt
• Freshly ground black pepper

1. Process the beets in a juice extractor, to make 1 cup juice.

2. In a small saucepan, boil the beet juice over high heat until it is reduced to ½ cup, about 10 minutes.

3. Stir in the vinegar and boil for 30 seconds. Add the oil and boil for 30 seconds, or until emulsified. Stir in the lime juice, salt, and pepper to taste and serve at once.

In advance: You can juice the beets and boil down the juice up to 2 days ahead; cover and refrigerate. The sauce will keep, covered and refrigerated, for up to 4 days. Reheat gently before serving.