Heat oven to 450°F. In large bowl, toss potatoes, cauliflower, onion, bell pepper, carrots, garlic, oil, 1/4 teaspoon salt and 1/8 teaspoon pepper. Arrange vegetables in single layer in ungreased 15x10x1-inch pan. Roast uncovered 20 minutes or until tender and lightly browned. Cool to room temperature, about 15 minutes. Reduce oven temperature to 425°F.