Navy Bean Soup

2 cups navy beans 1/8 tsp. pepper
3 quarts water 1/4 tsp mustard
1 minced onion 4 tbs butter
1/2 tsp celery salt 4 tbs flour
2 tsp salt 1 tbs minced parsley

Soak beans in water to cover overnight. Drain. Add water listed, onion, and celery salt and cook until beans are very soft. Press beans through course sieve. Add salt, pepper, and mustard, melt butter, blend in flour and add to the bean mixture. Heat to boiling point stirring constantly and cook for five minutes. Serve garnished with parsley. Serves 8 to 10