Boil salted water in a pot, then cook the pasta according to the package instructions.
Place a deep pan or skillet over medium-high heat and add olive oil.
Once the oil is ready, add the onion and garlic, and cook until the onion softens.
Add the chopped chorizo and cook for about 2 minutes, or until some of the fat begins to render.
Add crushed tomatoes, mix, and season with salt and pepper.
Cover with a lid and adjust the heat to medium-low.
Let simmer for 8 to 10 minutes (or until the pasta is ready) --- taste and adjust the seasoning as it simmers.
Add the cooked pasta and some pasta water (2 to 4 tablespoons, to start with).Note: See helpful tips in the post. Mix to combine, and evenly coat the pasta with the chorizo sauce.(Note: As you mix, you will see the sauce starting to pull together and coating the pasta nicely, giving it that ‘glossy’ look. Do not overcook!) Transfer to plates and grate some cheese on top, if desired.
Your chorizo pasta is now ready to serve --- enjoy!