Pour 250ml hot water over the mushrooms and let soak for 1 hour. After soaking, remove mushrooms and squeeze out excess water; set the water aside for later. Roughly chop the mushrooms.
Bring the stock to the boil in a saucepan; cover, reduce heat to low and keep warm.
Heat 3 tablespoons of the olive oil in a pan over medium heat. Add garlic and cook for 2 minutes, then add the mushrooms and cook for 5 to 6 minutes, or till soft. Add the rosemary, salt and pepper. Remove garlic cloves and discard. Pour in 120ml of the wine and raise the heat to medium high. Let simmer till the alcohol burns off, then remove from heat and set aside.
Melt 30g of the butter with the remaining tablespoon of olive oil in a saucepan over medium low heat. Add shallot and cook and stir till soft. Add rice and cook and stir for 3 minutes. Pour in remaining 120ml white wine and simmer till wine is just absorbed.
Add a ladleful of the hot stock to the rice mixture; stir and cook till the stock is just absorbed. Add another ladleful of stock and repeat this process till rice is tender, 15 to 18 minutes. Halfway through cooking the rice, start to gradually add the mushroom soaking water along with the stock.
Once rice is tender, remove risotto from heat and stir in the the remaining 30g of butter and the Parmesan. Season to taste, then let rest for 3 to 5 minutes before serving.