Pour the extra virgin olive oil into a large pan, add the red pepper flakes, and place over medium-low heat. Cook gently for about 3 minutes.
Remove the pan from the heat and add the garlic. Stir it in the oil for about 20 seconds, then add the crushed Italian tomatoes.
Add salt and sugar to the mix. Cook the mixture on low heat for 20 minutes, stirring occasionally.
While the sauce simmers, prepare the chicken breasts. Pat them dry with a paper towel.
Using a sharp knife, carefully cut through the middle of each chicken breast to create two fillets.
Cover the fillets with plastic wrap and gently pound the thicker ends until they are an even thickness. Season both sides with salt and black pepper.
In a heavy pan, heat olive oil over medium-high until shimmering. Carefully add the chicken fillets to the pan. Cook for about 3 to 4 minutes on each side until golden brown. Remove and tent with foil to keep warm.
In a large pot, bring water to a boil. Add a tablespoon of salt before adding the rigatoni. Cook for 1 minute less than the package instructions state. Reserve a cup of the cooking water, then drain the pasta.
Add the drained rigatoni to the sauce along with a ¼ cup of the reserved cooking water. Toss to coat.
Cook the pasta in the sauce over low heat for about a minute, adding more water if necessary.
Finally, add the baby spinach and toss until it wilts.
Before serving, taste for seasoning. Top with the cooked chicken fillets, garnish with fresh parsley, and sprinkle with grated parmesan.
