Creamy Tomato Soup

1. Put the oil, onions, celery, carrots, potatoes and bay leaves in a big casserole dish, or two saucepans. Fry gently until the onions are softened – about 10-15 mins. Fill the kettle and boil it.
   10–15 minutes
2. Stir in the tomato purée, sugar, vinegar, chopped tomatoes and passata, then crumble in the stock cubes. Add 1 litre boiling water and bring to a simmer. Cover and simmer for 15 mins until the potato is tender, then remove the bay leaves. Purée with a stick blender (or ladle into a blender in batches) until very smooth. Season to taste and add a pinch more sugar if it needs it. The soup can now be cooled and chilled for up to 2 days, or frozen for up to 3 months.
   15 minutes
3. To serve, reheat the soup, stirring in the milk – try not to let it boil. Serve in small bowls with cheesy sausage rolls.

Cooking notes

Scaling works best when you weigh ingredients rather than measure by volume — small differences in packing can compound at higher multipliers.

For volume-to-weight conversions of any ingredient — flour, sugar, butter, salts — use the ingredient converter. To translate the recipe's oven temperature between °C, °F and gas mark, see the temperature converter.

When you scale this recipe up or down, remember that cooking time does not scale linearly. A doubled cake takes longer, but not twice as long; a doubled soup takes roughly twice as long. The cooking-time guide gives sensible starting estimates by dish geometry.