Place a frying pan on a medium heat, add the olive oil, and fry the onion until translucent.
Then add the garlic and cook for another minute until fragrant.
Add the rice and toast it for a couple of minutes until the grains are hot to touch.
Pour in the wine if using and cook for a few more minutes until it evaporates.
Start to add the stock one ladleful at a time, allowing the liquid to be absorbed before adding more. Continue this process for about 15-20 minutes until the rice is creamy and cooked to your desired level of doneness.
Meanwhile, place a frying pan on a high heat, add ⅔ butter. Add the mushrooms when the pan comes to heat and the butter starts to bubble, fry for a few minutes until they begin to brown and set them aside.
Reduce the heat of the pan to medium and add the remaining butter and fry the sage leaves for a few minutes until they become crispy and set them aside.
Remove the pan from the heat and add the pumpkin purée, balsamic vinegar, Parmesan, salt and pepper and stir until all the ingredients are incorporated.
Serve immediately topped with mushrooms and crispy sage leaves.