1/4 cup butter/margarine
1 lb yellow onions, skin removed and sliced
3 cups beef broth (or vegetable broth for vegetarian)
1/4 cup cornstarch
1/2 cup cold water
In a saucepan melt margarine, then add onions. Cover saicepand and cook gently over medium-low heat for 20-30 minutes or until onions are soft. Remove lid, then continue to cook until brown and carmelizing. Add broth (plus salt to taste if desired), cover and simmer 30 minutes. In a small bowl combine cornstarch and water, then pour into soup, stirring well. Continue to cook, stirring until thickened. Cool and freeze in portion sizes.
To cook: Reheat on stovetop or in microwave. Top with cheese and/or croutons, use broiler to brown cheese if desired.