Remove all the membrane from the monkfish (this is important, otherwise cooking will turn it an unpleasant grey). Cut the two fillets away from the central bone and then divide the fillets into 6 equal pieces. Season the monkfish and coat it evenly with the flour. In a large shallow pan heat the olive oil and butter, then add the fish and cook for 2 minutes on each side. Remove the fish; add the shallots, garlic and girolles, and cook on a low heat for 5 minutes, stirring frequently. Increase the heat, return the monkfish to the pan, add the wine and simmer, covered, for 5 minutes. Remove the lid from the pan and allow the liquid to evaporate by half. Add the cream and simmer for 2 minutes to allow the sauce to thicken slightly. Add the chopped parsley, and serve.