In a pot with salted boiling water, cook the pasta until al dente. Reserve a cup of pasta water.
Using another pan, render the chorizo and sauté until crisp.
Add cooked pasta in the pan of chorizo.
Add the spinach, chili flakes, freshly cracked black pepper and some of the pasta water.
While still on heat, stir well and cook until the spinach is wilted. Serve immediately!