1. Preheat your oven to 190°C/Fan 170°C/Gas 5. Rinse and halve the squash and scoop out the seeds with a spoon (you can compost these or roast them to make a snack). Slice each squash half into around 5-6 wedges and place them in a roasting tin (no need to peel, although you can if you prefer to).
2. Drizzle 1 tbsp oil over the squash wedges, then dust them with 1/2 tbsp Jamaican jerk seasoning and a pinch of salt. Rub the seasoning and oil into the squash. Slide the tin into the oven and roast for 30-40 mins, till the squash wedges are tender when pierced with a fork, and a little charred around the edges.
3. While the squash wedges roast, make the rice and peas. Peel and finely chop the onion. Place a medium-sized pan on a medium heat and add 1/2 tbsp oil, the onion and a pinch of salt. Fry, stirring often, for 8 mins till the onion has softened a little but hasn't picked up too much colour - turn the heat down if the onion starts to brown.
4. While the onion fries, peel and finely chop the garlic. Drain the beans and rinse them under cold water. Have the chilli and scoop out the seeds and white pith (or leave them in for a hotter flavour). Finely chop the chilli. Stir the garlic, chilli and beans into the onion. Add most of the thyme sprigs (keep a small sprig back for garnishing). Gently stir to mix everything together.
5. Tip the rice into a sieve, rinse under cold water then tip the rice into the pan. Stir to mix. Pour in the coconut milk. Half fill the tin with water (around 100ml) and add that too. Pop a lid on the pan and bring it to the boil, then turn the heat down and very gently simmer the rice for 8-10 mins till it has absorbed all the liquid and become tender.
6. When the rice has absorbed all the liquid, take it off the heat and leave it in the pan with the lid on for at least 5 mins - this will steam the rice and finish cooking it. The rice will keep warm in the pan for up to 15 mins.
7. When the squash wedges are ready, take them out of the oven. Fish the thyme sprigs out of the rice.
8. Divide the rice between 2 warm plates and top with the squash wedges and handfuls of lamb's lettuce. Pick a few thyme leaves off the remaining sprig and scatter over the plates to garnish. Serve straight away.