Roasted beets with mint yogurt sauce

Preheat oven to 425 degrees. In a 9-by-13-inch baking dish, toss beets with olive oil. Season with salt and pepper. Cover dish tightly with foil and roast until tender when pierced with a knife, 45 to 60 minutes, depending on size. When cool enough to handle, rub beets with a paper towel to remove skins. Meanwhile, in a small bowl, whisk together yogurt, mint, cumin, and lemon juice; season with salt and pepper. Spoon yogurt sauce over beets and serve.