Core the tomatoes and submerge them in boiling water for 2 minutes. Drain the tomatoes and peel off the skins. (Skip this step if you are using peeled tomatoes)
Mash the tomatoes thoroughly until achieving a saucy consistency.
Heat olive oil in a pan over medium heat. Add garlic cloves and chili peppers, cooking for 2 minutes until fragrant. Incorporate the mashed tomatoes into the pan, seasoning with a pinch of salt. Stir the mixture with a wooden spoon and bring to a boil.
Reduce heat, cover, and simmer for 15–20 minutes, stirring occasionally to allow flavors to meld and the sauce to thicken.
Meanwhile, cook pasta according to package instructions. Before draining, reserve about 1 cup of the starchy cooking liquid.
Once pasta is cooked, drain it directly into the tomato sauce pan.
Return pan to heat and stir the pasta and sauce together for 30 seconds, adding 2–3 tablespoons of the reserved pasta cooking water to help sauce adhere to penne.
Remove pan from heat and toss in fresh parsley, stirring to combine.
Plate the penne arrabbiata, topping with extra Arrabbiata sauce from the pan.
Garnish with grated Pecorino cheese for added flavor if desired.