Cheese and Onion Soup

1-2 tbsp/15-30ml oil
2 medium onions, sliced
5 cups/1.1 l/2pts stock
250g/8oz potatoes
1 1/2 cups/175g/6oz grated cheddar cheese
salt
soy sauce
serves 4-6
Heat oil in a large saucepan and stir-fry onions until lightly browned. Add stock and bring to the boil.
Meanwhile, peel the potatoes and grate them into the saucepan. Turn down the heat and simmer until potatoes have cooked and soup has thickened.
Add the grated cheese, stirring to melt. Season to taste with salt and soy sauce. Serve with whole wheat bread and a crisp green salad.