Onion sauce

• 1 tablespoon butter
• 1 tablespoon flour
• 2 onions
• 1 teaspoon sugar
• 1 tablespoon tomato sauce
• 1-2 tablespoons vinegar or lemon juice
• 2 cups beef broth or water
• salt

Chop the onions and fry in butter until yellowish. Add the flour, fry a little and then add the broth, stirring continuously. Add salt, sugar and tomato sauce and let boil for 10 minutes. Then add the lemon juice and simmer until thickened. To be served with beef or pork.