In another medium saucepan, melt 2 tablespoons of the butter over medium heat. Add the shallot and saute for about 3 minutes. Add the rice and stir to coat with the butter. Add the wine and simmer for about 3 minutes until the wine has been absorbed. Add 1/2 cup of the simmering broth and stir until almost completely absorbed, about 2 minutes. Continue cooking the rice, adding the broth 1/2 cup at a time, always stirring. Continue this until the rice is tender to the bite. Remove from the heat. Stir in the remaining tablespoon of butter, Parmesan, Mascarpone cheese, the lemon zest and juice, and the salt and pepper. Serve immediately.
