Cook the pasta in slightly salted water. Heat the butter in a pan on a medium heat, add the onion and fry. Chop the pork tenderloin into bite-sized pieces, and add to the onion. Fry, then add the chanterelles, season with salt and pepper. Cover, and simmer for a while. After about 5 minutes take the cover off, fry mixing with a spoon from time to time. Add the cream. Pick and finely chop the parsley and sprinkle over. Stir, bring to the boil, and then reduce to a simmer for some time. Serve with penne. Top-notch!