The extra starch in Arborio rice gives risotto its creamy texture; here Parmesan cheese makes it even creamier.
Heat chicken stock in a medium saucepan. Keep hot during preparation.
Heat the butter and oil in a large, heavy saucepan over medium heat. Add the garlic and shallots, and saute, stirring occasionally, until softened and translucent, 3 to 4 minutes. Do not brown. Add the rice, and stir to coat. Cook rice, stirring frequently, until well coated and grains start to appear translucent, about 2 minutes. Add the white wine, and stir constantly until it has evaporated, about 2 minutes.
Add 1 cup of the hot stock, and cook, stirring constantly, until almost all of the liquid has evaporated. Then add hot stock, 1/2 cup at a time, stirring constantly until each addition is absorbed before adding the next (reserve about 1/2 cup stock for serving). Cook until rice is tender but still firm in the center (a total of 20 to 25 minutes).
Remove pan from heat, and stir in 2 teaspoons lemon zest, 3/4 cup Parmesan cheese, salt, and pepper. Add some of the remaining stock a little at a time to reach desired consistency (it should be fairly loose). Serve immediately, garnished with additional lemon zest, if desired, and Parmesan cheese.