Potato Soup

1 small onion chopped
6 stalks celery
6-8 potatoes
1/4 c. butter
1/2 c. flour
2 c. milk
1 t. salt
1 t. mustard powder
1/2 t. white pepper
1/4 c. chopped cooked bacon 
In a big stock pan, add vegetables and just enough salted water to cover vegtables. Bring to boil and cook until vegetables are tender.  In a seperate pan, melt butter, add flour to make a roux.  Cook 1 minute and slowly add milk while stirring.  Keep stirring until smooth and thick.  Add salt, mustard powder, and white pepper.  Add white sauce to vegetables.  Heat though.  Sprinkle top with a little cooked bacon.  This is Kaylee's favorite.  The kids love taking this soup to school in their lunch.