This recipe is from manyveggierecipes.com and is simple and quick.  It does call for a lot of ingredients, but the result is worthwhile.  Once you have all of these odds and ends, you can make this quickly at any time.  

Ingredients:

3/4 cups Water
2 tbsp Unbleached flour
1 tbsp Tahini
1/4 cup Soy milk
2 tbsp Vegan margarine
1 tsp Italian seasoning
1/2 tsp Garlic salt
1 Vegetable bouillon cube or 1 tbsp vegan broth powder
1/4 tsp Ground coriander
1 tbsp Nutritional yeast

Instructions:

Combine the water, flour and tahini in a small jar. Shake the contents until the tahini dissolves.
Pour the mixture into small sauce pan and add the remaining ingredients.
Heat, stirring constantly, until gravy thickens. Do not let it boil.