Step 1

Heat the oil in a large saucepan - as large as possible. Peel and finely chop the onion and fry gently for 2-3 minutes until starting to soften.

Step 2

Add the garlic and ginger and continue to cook gently for a further 2-3 minutes.

Step 3

Meanwhile, trim the ends from the marrow or courgette. If the skin is fairly tough you may want to cut it off, but it is edible and this usually isn't necessary. If the centre is stringy with fairly large seeds, scoop this out and just use the flesh in the soup.

Step 4

Chop the marrow into chunks about 1cm square and add them to the saucepan along with the curry powder. Season well with salt and black pepper, and leave to cook over a medium heat for 10-15 minutes or until the marrow has released its liquid and this has cooked off.

Step 5

Peel the potato and chop it into cubes. Drain and rinse the cannellini beans. Add the potato, beans, coconut milk and vegetable stock to the saucepan and bring to the boil.

Step 6

Reduce to a gently simmer and cook for 10 minutes until the potato is tender.

Step 7

Squeeze in the lemon juice then blitz to a smooth purée. Keep going for a minute or two - you want the soup to be velvety smooth.

Step 8

Taste and adjust seasoning as required then serve.