For the jerk lamb, blend all of the ingredients, except the lamb, in a food processor to a purée.
Spread the mixture over the lamb until completely covered and set aside to marinate in the fridge for at least four hours. Remove the lamb from the fridge and allow to come to room temperature.
Preheat the oven to 200C/400F/Gas 6.
Heat an ovenproof frying pan until hot, add the lamb and fry on both sides until browned.
Roast in the oven for 10-12 minutes (for medium), then remove and set aside to rest for 10 minutes.
For the chilli butternut squash, heat the oil in a lidded frying pan and fry the spring onions, allspice, chillies and thyme for 1-2 minutes, or until the onion has just softened.
Add the butternut squash and fry for 4-5 minutes, or until pale golden-brown.
Cover the pan with a lid and continue to cook for 3-4 minutes, or until just softened.
Add the sugar, lime juice and mango and cook for another 2-3 minutes, or until tender and slightly sticky.
Stir in the coriander and mint and season with salt and freshly ground black pepper.
For the apple salad, heat 1cm/½in of vegetable oil in a deep, heavy-based saucepan and heat until a small cube of bread sizzles and turns golden-brown when dropped into it. (CAUTION: hot oil can be dangerous. Do not leave unattended.)
For the apple salad, fry the apple slices in the vegetable oil for 1-2 minutes, or until crisp. Remove with a slotted spoon, drain on kitchen paper and season with a little salt. (You may need to cook the apple slices in batches.)
Whisk the mustard, vinegar and olive oil together in a bowl and season with salt and freshly ground black pepper.
Mix the frisée leaves, pomegranate seeds and apple slices together in a bowl. Add some of the dressing and stir until well combined.
To serve, spoon the butternut squash into the centre of the plate. Carve the lamb into thick slices and place a few slices across the pumpkin. Pile a little salad on top of the lamb and finish with a scattering of coriander and amaranth cress.