To Make the Mushrooms Sauce Ahead: Complete the sauce recipe fully. Allow to cool, then transfer to a glass storage container and keep in the fridge for up to 3 days. When ready to serve, spoon the sauce into a large skillet and gently warm over medium-low heat until the sauce is steaming, 5-8 minutes. If the sauce thickens up, add additional cream to thin. Taste and season as needed with salt and pepper.