Add the pasta shells to a pot of boiling salted water and cook for 10–12 minutes, or until al dente.
Meanwhile, heat the olive oil in a large pan and add the pancetta. Fry for a few minutes until it is golden brown, then add the leeks, mushrooms and a little salt and pepper. Stir over high heat for 6–8 minutes until the leeks are tender.
Drain the pasta and immediately toss with the pancetta, leeks and mushrooms. Stir in the crème fraîche and season with salt and pepper to taste. Scatter over the chopped parsley to serve.
Copyright © Gordon Ramsay