1Heat olive oil in a large, heavy-bottomed pot or Dutch oven over medium heat. Add the crumbled chorizo and cook, breaking it up with a spoon, until browned and cooked through. Remove chorizo with a slotted spoon and set aside, leaving rendered fat in the pot.

2Add diced onion to the pot and cook in the chorizo fat over medium-low heat until softened and translucent, about 5-7 minutes. Add minced garlic and sliced mushrooms, increasing heat slightly, and sauté until mushrooms release their liquid and begin to brown, about 8-10 minutes.

3Stir in the Arborio rice and red pepper flakes, toasting for 2 minutes until the edges of the grains are translucent. Pour in the white wine and stir continuously until it has completely evaporated, about 2-3 minutes.

4Begin adding the hot broth, one ladleful at a time (about 1/2 cup), stirring frequently until almost all the liquid has been absorbed before adding the next. Continue this process for 20-25 minutes, or until the rice is creamy but still firm to the bite (al dente).

5Stir the cooked chorizo back into the risotto. Remove the pot from the heat and stir in the Parmesan cheese, unsalted butter, chopped parsley, lemon zest, and lemon juice. Season with salt and freshly ground black pepper to taste.

6Cover the pot and let the risotto rest for 2-3 minutes to allow the flavors to meld and for it to achieve its ultimate creaminess. Serve immediately, garnished with extra Parmesan cheese and fresh parsley, if desired.