How to Make It
Season the chicken breast with salt and pepper. In a small pan, heat 1 tablespoon of the extra-virgin olive oil over medium high heat. Add the chicken and cook for 1 minute. Turn the chicken, reduce the heat, cover the pan and cook for 8 minutes. Remove from the heat and leave covered for 10 minutes, then shred the chicken with 2 forks.
Meanwhile, in a large pot of boiling salted water, cook the pasta according to package directions.
In a large frying pan, heat the remaining 1/4 cup of extra-virgin olive oil over medium heat. Add the onion and cook for about 5 minutes, or until it softens. Reduce the heat to low, add 1/2 teaspoon each of sea salt and sugar, and continue to cook for 10 minutes, until the onions are very soft and caramelized. Add the chorizo and chile flakes and cook for 3 minutes, or until the chorizo has cooked through and starts to brown. Add the spinach and cook for 1 minute, until it starts to wilt.
Add the penne and chicken to the pan and toss it to coat well. Remove from the heat, stir in the 1/2 cup Parmigiano-Reggiano cheese and season generously with sea salt and freshly ground pepper. Serve with extra Parmigiano-Reggiano on the side.