Speedy Cream Of Potato Soup

2 tablespoons butter or margarine

1 medium onion -- chopped

4 1/2 cups water

1/2 teaspoon salt

dash pepper -- if desired 2 1/4 cups Betty Crocker Potato Buds Mashed

potato mix (dry) shredded cheddar cheese -- if

chopped green onions -- if desired

Melt margarine in 2 qt saucepan over medium heat. Cook onion in margarine about 3 minutes, stirring occasionally, until tender. Stir in water, salt and pepper. Heat to boiling; remove from heat. Stir in potato mix until dissolved. Serve with cheese and onion tops.