- 750g sweet potatoes
 - 200ml coconut milk
 - 23g Thai green curry paste
 - 40g peanut butter
 - A thumb of ginger
 - 1 garlic clove
 - 1 chilli
 - A handful of coriander
 - 1 lime
 - A 250g punnet of cherry tomatoes
 - 50g lamb's lettuce
 
- Sea salt
 - Freshly ground pepper
 - 1 tbsp olive oil
 
- 1.
Heat your oven to 180°C/Fan 160°C/Gas 4. Scrub and slice the sweet potatoes as thinly as possible. Lay the slices in a medium-sized baking dish.
 - 2.
Finely chop the chilli, flicking out the seeds for a milder heat. Peel and grate the ginger and garlic. Zest and juice the lime. Roughly chop the coriander stalks, saving the leaves for later.
 - 3.
Tip the chilli, ginger, garlic, coriander stalks, lime zest and half the juice into a food processor. Squeeze in the curry paste and peanut butter. Pour in the coconut milk. Blitz to combine. Taste and season.
 - 4.
Pour the fragrant coconutty sauce over the sweet potato slices. Tumble together with your hands, then spread out.
 - 5.
Cover the dish with foil and seal the edges tightly. Cook for 30 mins. Remove the foil and cook for a further 20 mins till golden. Check the sweet potato is done by piercing with a knife. If still firm, return to the oven and cook for another 5-10 mins.
 - 6.
Whisk the remaining lime juice with 1 tbsp oil and some seasoning. Quarter the tomatoes. Toss the tomatoes and lamb's lettuce with the dressing. Serve with the sweet potato gratin, garnished with chopped coriander leaves.
 - 7.
 
- Tip
No processor?
Simply finely chop the chilli. Finely grate the ginger and garlic. Whisk together in a bowl with the peanut butter, coconut milk, curry paste, coriander stalks, lime zest and juice.