Onion Cheese Soup

1 large onion, chopped
3 tablespoons butter
3 tablespoons all-purpose flour
1/2 teaspoon salt
Pepper to taste
4 cups milk
2 cups (8 ounces) shredded Colby-Monterey Jack cheese
Seasoned salad croutons
Grated Parmesan cheese, optional

In a large saucepan, saute the onion in butter. Stir in the flour, salt and pepper until blended. Gradually add milk. Bring to a boil; cook and stir for 2 minutes or until thickened. Stir in cheese until melted. Serve with croutons and Parmesan cheese if desired. Makes 6 servings.