Heat olive oil in a large skillet over medium heat and add the cubed potatoes and a pinch of salt. Cook, stirring frequently, for 6-7 minutes until lightly golden. Transfer to a bowl.
Add the diced onion to the skillet and cook for 4 minutes, then add the minced garlic and red pepper flakes, if using.
Stir in the tomato passata. Pour 1 1/2 cups of water in the jar, swirl it around to gather the excess sauce and add to the skillet. Add salt, to taste.
Bring to a boil and return the potatoes to the skillet. Then lower to a simmer, cover and cook until the potatoes are fork tender, about 20 minutes.
Once the potatoes are tender, loosely cover the skillet and let the sauce simmer for an additional 40 minutes to allow it to thicken. Taste and adjust seasoning if necessary.
Meanwhile bring a large pot of salted water to a boil. Cook your pasta, drain and add to the skillet with the sauce. Toss to combine well. Add a ladle or two of pasta cooking water to loosen the sauce, if needed.
Drizzle a little extra olive oil over the pasta before plating. Serve with grated Parmigiano or Pecorino Romano cheese at the table.
Notes
Substitutions and Variations-Recommended pasta choices for this dish include medium or longer length pastas such as rigatoni; penne; or spaghetti. -If you prefer a higher potato to pasta ratio, add an extra potato or two to the recipe. -Toss a few leaves of fresh basil into the sauce for extra flavor.Tips-When tossing the pasta into the sauce, add a ladle or two of pasta cooking water to loosen the sauce. The starchy water also helps the sauce cling to the pasta.StorageKeep leftovers refrigerated for up to 3 days.Please note that the nutritional information provided is approximate and may vary according to exact ingredients used and portion size.