2 large onions, peeled and sliced
2 Tbsp butter
1 Tbsp standard white flour
¾-1 cup beef stock (or vegetable stock)
1 tsp Worcestershire sauce, optional
1 Put onions in a medium frying pan (skillet) with 2 tablespoons of butter and cook gently for about 35-40 minutes, stirring often, until tender and nicely golden. Don’t hurry this or the onions will scorch and taste harsh.
2 Stir in flour, then stock and Worcestershire sauce. Bring to a gentle boil, stirring, season with ¼ teaspoon of salt, and cook gently for 1-2 minutes, stirring. Cover with a lid and turn off the heat. Reheat gently when required (add a little extra stock or water if the sauce is too thick).