Heat oven to 180°C and warm the roasted chestnuts on a baking tray for approximately 15mins. It is possible to use packaged chestnuts for this recipe. Leave the oven on as this baked risotto will go back into the oven.
Put Porcini mushrooms in a bowl and pour over boiling water. Allow to stand for 10 minutes and then drain, reserving 1 cup of the water for use later. Roughly chop the mushrooms.
In a saucepan melt the butter, then add garlic, porcini mushrooms, and shallots and stir until the onion has become transparent. Add the rice, and stir until the rice becomes slightly transparent on the edges.
Add the champagne and stir for a few minutes until the champagne has reduced slightly in volume.
Take the drained liquid from the porcini mushrooms into a measuring jug and add vegetable stock (or chicken stock) up to 3 cups. The porcini liquid is a great stock base and you can use more of less of this liquid depending on your preference.
Put the risotto mix into a baking dish, add the 3 cups of vegetable stock, season with salt and pepper, and cover with aluminium foil. Bake for 45 – 50 mins until the rice has absorbed all of the liquid and is tender. Stir occasionally to ensure the liquid is absorbed evenly.
Remove risotto from the oven and once the liquid is absorbed. Add the parmesan cheese, and stir through to melt. (If you want to add extra indulgence to this dish, stir through another good tablespoon of butter before adding the parmesan cheese). Check again for seasoning, adding salt and pepper to taste.