Creamy Vegetable Chowder

2 cups diced and peeled potatoes
1 cup diced celery
1 onion, finely diced
3 cups water
3 cups milk
1 - 28 ounce can of tomatoes, chopped
1/4 cup butter
1/4 cup flour
2 teaspoons salt
1 tablespoon steak sauce
1 teaspoon dry mustard
4 slices American cheese, diced
pepper to taste

In a large saucepan or stockpot, combine the potatoes, celery, onion, salt, and water. Cover and bring to a boil; then reduce the heat and simmer until the potatoes are tender, about 15 minutes.

In another saucepan, melt the butter over medium heat. Add the flour and mustard and mix them into the butter to form a paste. Stir in the milk and steak sauce and blend until smooth. Stir in the cheese and continue stirring until the cheese is completely melted. Then add this mixture to the vegetables. Add the tomatoes and pepper and heat through; do not allow the soup to boil. Serve hot.