Easy Cheddar Potatoes

Smooth, creamy and delicious, this easy-to-make mashed potato side goes great with any meat main dish! 2 cups water 3 tablespoons butter or margarine 3/4 cup milk 1-1/2 cups instant mashed potato flakes or buds 1 (10-3/4 oz) can condensed cheddar cheese soup 1/3 cup...