Preheat the grill to high. Line a baking tray with foil and arrange the sausages on the tray. Grill, turning frequently, until cooked through. When cool enough to handle, cut into chunks. Set aside and preheat the oven to 200ºC/fan 180ºC/gas mark 6.
Meanwhile, cook the pasta according to the instructions on the packet. Drain well.
Combine the tomatoes with the crème fraîche. In another bowl, mix half of this tomato sauce with all the pasta, spinach and sausages. Add the mixture to a 2-litre ovenproof dish, then pour over the remaining tomato sauce. Top with the grated cheese and bake for 20 minutes.