Put onion and marg in a pan to cook for 5 mins then add stock and water, add tin of tomatoes and passata and salt and pepper and cook. After some cooking make up some cornflour paste with milk and stir in soup to thicken.

You can top up with more milk if too thick. Add the sugar.
When done strain the soup you can use the tomato bits to make a patty.

Serve with gluten free buns.