In a large saucepan over high heat, add the butter with the oil.
Add the onion and sautee for a minute. Add the garlic and cook for a further minute.
Stir in the wine and cook for a few minutes until the volume has reduced by half. Season with a pinch of salt and pepper and add the mushrooms. Cook for around five minutes until the mushrooms turn slightly golden.
Add the cream and the nutmeg and cook lightly until the sauce thickens slightly. Season with the oregano, lemon juice and another pinch of salt and pepper if needed.
Serve hot over freshly cooked linguine or your favourite pasta.