1) Bring a large saucepan of salted water to the boil over high heat. Add the pasta and cook until tender but still firm to the bite, stirring occasionally, about 8 to 10 minutes.
2) Heat the oil in a large frying pan over medium-high heat. Add the shallots and garlic to the pan. Season with salt and pepper. Cook until soft, about two minutes. Add the mushrooms to the pan and season with salt and pepper. Cook until the mushrooms are tender, stirring occasionally, about 5 to 7 minutes.
3) Turn the heat to high. Add the wine and cook for three minutes until all of the liquid evaporates. Add the stock and simmer until the liquid has slightly reduced. Remove the pan from the heat. Add the mascarpone cheese and stir until creamy.
4) Drain the pasta, reserving about 240ml of the pasta water, and transfer to a serving bowl. Add the mushroom mixture and the Parmesan cheese. Season with salt and pepper, to taste. Toss well to coat the pasta, adding the reserved pasta water, if needed, to loosen the pasta.
Garnish with the chopped chives. Serve immediately.