Quarter the unpeeled potatoes. Cook, covered, in a small amount of boiling salted water for 20 to 25 minutes or until tender. Peel the paper-like outer skin off the garlic cloves. Add the whole garlic cloves to the potatoes for the last 15 minutes of cooking.
Meanwhile, cook green onion in margarine or butter until tender but not brown. Drain potatoes and garlic; mash potatoes and garlic with a potato masher or beat with an electric mixer on low speed.
Add green onion mixture, Romano or Parmesan cheese, and pepper. Gradually beat in enough milk to make potatoes light and fluffy. Makes 4 servings.