Stilton and spinach pasta

Bring a large pan of water to the boil and add the pasta. Cook for 10-12 mins, or as directed on the packet. Meanwhile, to make the sauce: Heat the olive oil in a saucepan and add the onion. Cook over a medium heat for 5-7 mins, stirring occasionally, until onion starts to turn pale golden. Stir in the crème fraîche and mustard and 125g (4oz) Stilton. Heat until the Stilton melts. Drain the pasta well and then add it to the sauce and mix well. Season. Add the spinach to the pan and continue to cook until the spinach wilts. Transfer the pasta to warm serving dishes and scatter the remaining Stilton cheese on top and serve immediately. (Not suitable for freezing).