Soften the onions: Melt 2 tablespoons of Butter in a large saucepan over a low-medium heat. Add 1 Onion (diced) and cook for about 3 minutes, until softened and just starting to colour.
Add the tomatoes: Stir in 2 tablespoons of Tomato puree and cook for about 30 seconds. This helps bring out more of its rich tomato flavour. Add 400 g of Chopped tomatoes.
Simmer: Add 500 ml of Vegetable stock (low salt), ½ teaspoon of Fine sea salt and ½ teaspoon of Ground black pepper. Bring to a gentle simmer and cook for 10 minutes.
Blend the soup: Blend until smooth, then taste and adjust the seasoning. If using Fresh basil, add it just before blending or scatter it over the finished soup.
If you prefer a thicker tomato soup, you can hold back around 100ml of the stock before simmering.Blend the soup first and then add as much of the remaining stock as you need to get the consistency you like.
Notes
For a thicker soup, hold back around 100ml of stock and add it after blending if needed.
Use good-quality tinned tomatoes as they provide most of the flavour.
Add fresh basil just before blending for a tomato basil variation.
Use low-salt stock if making the soup for young children.
Swap the butter for olive oil or plant-based butter to make the soup vegan.
If the tomatoes taste particularly acidic, a tiny pinch of sugar or a small splash of cream can help balance them.
Take care when blending hot soup, especially in a jug blender.