• Heat the olive oil in a large saucepan.
• Add 1 chopped onion, 2 cloves of chopped or crushed garlic and 1 stalk of chopped celery. Stir. Reduce the heat to low, cover the pan with a lid and sweat for 10 minutes until soft.
• Add 3 diced courgettes, stir and cover again. Continue to cook for 10-15 minutes until soft. Stir often to avoid sticking.
• Add 4 diced potatoes and a litre of hot vegetable stock. Bring to the boil then reduce the heat to low and simmer until the potatoes are soft.
• Blend with a hand held blender. If using a jug blender allow to cool first.
• Season to taste with salt and pepper and serve with croutons or sliced bread.

To make the croutons

• Preheat the oven to 180°C (fan)/200°C/gas mark 6.
• Cut the bread into chunks that are around 2-3cm square. Drizzle with olive oil and sea salt and mix well.
• Spread onto a non-stick baking tray. Bake for 10 minutes then turn. Return to the oven for a further 5 minutes but keep an eye on the croutons to make sure they don't burn.