Tuna Stroganoff

Ingredients

• 2 7-ozs. cans tuna (I use packed in water)
• 1 cup chicken-flavored bouillon (pareve)
• 1/2 cup chopped onion
• 1 8-ozs. can mushrooms
• 1/4 cup margarine
• 2 tbsp. flour
• 1/4 tsp. Worcestershire sauce
• 2 tbsp. ketchup
• 1/2 cup sour cream
• Pepper to taste