In a large pan (I use my wok!) gently fry onions in olive oil over a medium heat till soft, adding the garlic after 3 to 4 minutes.
Add the rice and stir for 1 minute before adding the mushrooms. Add the wine, if using, and once it mostly evaporates, add a third of the stock. Gently simmer for 30 minutes (or until the rice is soft), gradually adding more stock as required (as the pan starts to run out of stock) until it is all used.
Once all stock is reduced and rice softens, stir in Parmesan, parsley and salt and pepper to taste (I personally like a lot of pepper in mine).
Finally stir in butter before serving.
Try serving with garlic bread and asparagus or topped with fresh rocket for a bit of colour and variety on the plate