- Cook an stir Onion in butter in 3-quart saucepan on medium-high heat until tender.
- Add potatoes, water, celery and seasonings.
- Bring to a boil.
- Reduce heat; cover.
- Simmer 15 minutes or until vegetables are tender.
- Gradually add small amount of milk to flour, stirring until well blended.
- Gradually add flour mixture to hot vegetables, stirring constantly.
- Stir in remaining milk and Sausage; cook, stirring constantly, until mixture boils and thickens.
- Add American cheese; stir until melted.