Wash and soak 2 cups split peas. Drain the peas, reserving the liquid. Add enough water to the reserved liquid to make 10 cups. Adding peas again, cook covered for about 2 1/2 to 3 hours.
Add and simmer, covered, for 1/2 hour longer until vegetables are tender: 1/4 tsp. thyme, 1/2 cup chopped onions, 1 cup chopped celery with leaves, 1/2 cup chopped carrots.
Put the soup through a sieve.
Melt: 2 tbl. butter. Stir in it until blended: 2 tbl. flour. Add a little of the soup mixture, slowly. Cook and stir until it boils then stir it into the rest of the reheated soup. Correct the seasoning.
Makes about 8 cups.