Heat the oven to 200C/180fan/Gas 6 then lay the sausages, squash and onions in a shallow roasting tin. Divide the garlic into individual cloves and add to the tin unpeeled. Pour over the oil, scatter the spices and thyme, and season with sea salt and pepper.
Roast in the pre-heated oven for 15minutes then turn the sausages and vegetables and return to the oven for another 20 minutes adding the tomatoes in the last 10 minutes of cooking.
Divide onto 4 plates or bowls and serve with jacket potatoes or a green salad.