Peel and thinly slice the onions. Peel and grate the garlic. Warm a large pan on a medium heat and add 2 tbsp oil. Add the onions and fry gently, stirring occasionally, for 8 mins till glossy. Fill and boil the kettle.

While the onions fry, peel and chop the potatoes and sweet potatoes into bite-size chunks. Peel and thickly slice the carrots.

Add 2 tbsp Thai red curry paste and the peanut butter to a heatproof measuring jug with a pinch of salt and pepper. Pour in 500ml hot water from the kettle and stir.

When the onions have cooked for 8 mins, add the garlic to the pan and stir for 1 min. Add the potatoes, sweet potatoes and carrots to the pan. Pour in the tin of coconut milk and add the curry spiced peanut butter mixture. The liquid should just about cover the veg. Add more hot water if you need to. Stir, pop a lid on the pan and simmer for 12-15 mins till the potatoes are just tender.

While the curry simmers, finely shred the cavolo nero, discarding any thick or dry ends. When the curry has cooked for 12-15 mins, gently stir in the cavolo nero. Cook for 3-4 mins, without the lid on the pan (this helps keep the cavolo nero green), till the veg is tender when pierced with a knife and the cavolo nero has softened.

Taste the curry and add more salt or pepper if you think it needs it. Serve the curry in warmed bowls.