Cover potatoes with boiling water. Cook, covered, for 20 to 25 minutes or until tender. Drain; return potatoes to pan. Mash with potato masher or beat with mixer on low speed until smooth. Add cheese; beat until combined. Beat in milk until combined. Season with salt and pepper. Transfer to a 2-quart casserole; cover.
Bake in a 350 degree F oven for 25 minutes or until heated through. (Or, cover and chill up to 24 hours. To reheat, bake, covered, in a 350 degree F oven for 1-1/2 hours or until heated through.) Makes 8 to 10 servings.