- 2 garlic cloves
- A large thumb of ginger
- 1 lime
- A large handful of coriander
- 40g peanut butter
- 400ml coconut milk
- Sea salt
- Freshly ground pepper
- 1½ kg sweet potatoes
- 250g cherry tomatoes
TIP: This gratin can be stored in the fridge for up to 3 days, or in the freezer for up to 3 months. Defrost completely overnight. Reheat in a microwave till piping hot, or pop into an ovenproof dish, cover and bake for approx 20 mins till piping hot.
1. Preheat your oven to 200°C/Fan 180°C/Gas 6. Peel and grate the ginger and garlic into a large bowl. Zest and juice in the lime. Finely chop the coriander stalks and half of the leaves. Add them to the bowl. Set the remaining leaves to one side.
2. Add the peanut butter to the bowl. Shake the coconut milk tin and pour that in. Add a large pinch of salt and pepper and whisk together well.
3. Scrub the sweet potatoes and slice them as thinly as you can – ½cm thick is ideal. Tumble them into a large casserole or baking dish.
4. Pour over the coconut mix and gently turn the sweet potatoes over so each slice is coated. Scatter the whole cherry tomatoes over the top. Clamp on a lid or cover tightly with foil. Slide into the oven for 45 mins.
5. Remove the dish from the oven after 45 mins. The sweet potato slices should be tender when pierced with a knife. Slide the dish back into the oven, uncovered, for 15 mins to crisp the top up slightly.
6. Serve the sweet potato gratin on warm plates, topped with the remaining coriander leaves.