Heat the broth in a medium saucepan over medium heat to maintain a simmer.
In a large saucepan, heat the butter and oil over medium heat until butter is melted, about 1 minute. Stir in the shallots and cook until translucent but not browned, about 5 minutes. Stir in mushrooms and cook until golden, about 5 minutes. Sprinkle with salt and pepper.
Add rice, stirring until all grains are coated and translucent around the edges, about 3 minutes. Add the wine, scraping any brown residue from the bottom of the pan and cook, stirring often, until most of the liquid has been absorbed, about 2 minutes.
Cook the rice, stirring often, and adding 1 cup (250 mL) of the simmering broth at a time (stirring until almost all the broth has been absorbed before adding more – this is what produces the creamy texture) until the rice is al dente, about 45 minutes. If needed, add up to 1 cup (250 mL) extra broth if rice is too thick. Stir in the peas with the last addition of broth.
Remove from heat and stir in the lemon zest, Parmesan and parsley. Let sit covered for 10 minutes before serving in warmed bowls or plates with additional Parmesan and fresh cracked pepper, if desired.