Crush garlic cloves. In small bowl combine garlic and yogurt. Cover and refrigerate 1 hour. If using fresh beets, place in pan of cold water to cover and bring to boil. Simmer until tender enough to be pierced through by fork, 30-60 minutes, depending on size. Drain and rinse until cold running water until cool enough to handle. Slip off peels and trim remaining greens. Dice. Saute onion in butter until golden brown. In bowl mix onions with beets and yogurt. Makes 8 servings. Each serving contains about: 96 calories; 123 milligrams sodium; 11 milligrams cholesterol; 4 grams fat; 12 grams carbohydrates; 4 grams protein; 0.72 gram fiber.