1) Cut the stems off the oyster mushroom and slice them as thick as the mushroom caps.
2) If you're using large button mushrooms instead, halve them.
3) In a microwavable dish, add butter, mushrooms, cognac, lovage leaves and microwave for 3 minutes, turning them over halfway through the process.
4) On a heated serving platter, plate the cooked mushrooms minus the juices.
5) Pour cream into the juices left behind in the dish and microwave for another 45 seconds uncovered.
6) Season with salt and ground pepper.
7) Serve the Mushrooms with Cream and Cognac by pouring the warm creamy liquid over the plattered mushrooms.