Preheat the oven to 220°C/200°C fan-forced. Finely chop the onions and garlic cloves (see Note 2). Roughly chop the mild chorizo (see Note 3).
In a large frying pan, heat a drizzle of olive oil over a medium-high heat. Add the onion and chorizo and cook for about 5 minutes until golden. Add ½ the garlic and cook for 30 seconds, until fragrant. Add the butter and arborio rice and stir to coat the rice. Pour in the water and crumble in the vegetable stock cubes. Bring up to the boil, then remove from the heat.
Transfer the risotto to a medium baking dish, cover tightly with aluminium foil and bake for 15 minutes. Remove the dish from the oven and stir through a splash of water. Re-cover with the foil and bake for a further 15 - 20 minutes, until the liquid has been absorbed and the rice is al dente (see Note 4).
While the risotto is baking, slice the cherry tomatoes in half. Pick over the thyme leaves. Place the cherry tomatoes, thyme, 2 tablespoons olive oil and a good pinch of salt and freshly ground black pepper on an oven tray lined with baking paper. Toss to coat, then roast for about 20 minutes until fragrant and lightly charred. In the meantime ; finely chop the parsley, zest one of the lemons to get a pinch of zest, then cut both lemons into wedges.
When the risotto has 5 minutes of cook time remaining, wipe out the frying pan and return to a medium-high heat with 1 tablespoon olive oil. Add the banana prawns and cook, tossing, until pink and starting to curl, about 3 minutes. Add the chilli flakes (red pepper flakes) (if using) and the remaining garlic and cook a further 30 seconds until fragrant. Remove the pan from the heat and add a squeeze of lemon juice, a small handful of parsley and a pinch each of salt and freshly ground black pepper.
Stir the grated Parmesan cheese through the risotto until melted. Add the baby spinach leaves, the remaining parsley (reserve some for garnish) and the lemon zest and stir to combine. Season to taste with salt, pepper and a squeeze of lemon. Gently fold in the roasted cherry tomatoes.
Divide the risotto between bowls and top with the garlic prawns. Sprinkle with the reserved parsley and serve with the remaining lemon wedges.