Preheat oven to 425 F.

Toss cauliflower, oil, garlic, marjoram, salt and pepper in a large bowl. Spread on a large rimmed baking sheet and roast until starting to soften and brown at the bottom, 15 to 20 minutes.

Toss the cauliflower with vinegar and sprinkle with cheese. Return to the oven and roast until the cheese is melted and any moisture has evaporated, 5 to 10 minutes more.

Exchanges: 0 Grain(Starch); ¹⁄₂ Lean Meat; 1 Vegetable; 0 Fruit; 2 Fat