In a large skillet, heat the olive oil over medium heat. Add the chopped onion and cook for about 5 minutes, until softened. Stir in the minced garlic and cook for an additional minute until fragrant.
Add the sliced chorizo to the skillet and cook for 3-4 minutes, until it starts to brown and release its oils.
Stir in the Arborio rice and cook for 1-2 minutes, allowing the rice to toast slightly.
Begin adding the warmed broth one ladle at a time, stirring frequently. Wait until the liquid is mostly absorbed before adding the next ladle. Continue this process for about 18-20 minutes, or until the rice is creamy and al dente.
Once the rice is cooked, stir in the chopped spinach and grated Parmesan cheese. Season with salt and pepper to taste.
Remove from heat and let it sit for a couple of minutes. Serve garnished with fresh parsley.