Preheat the oven to 190°C.
Peel the sweet potato and cut it into bite-sized chunks. Cut the tomatoes in half. Scatter them in a baking tray. Add the minced garlic, then dust everything with the spices and drizzle with olive oil. Season with salt and pepper, then toss well.
Cover the dish with foil and bake in the oven for 25 minutes. Remove the foil, toss again. Add the pasta, if the tomatoes haven’t released enough liquid - it shouldn’t be dry. Bake for another 5 minutes or until the sweet potatoes have cooked through.
Now add the peas and spring onions. Put the prawns on top, cover the dish again and bake for 5 minutes, until the prawns have turned pink.
Scatter the parsley leaves on top and serve.