Bring a large pot of well-salted water to a boil. Cook the rigatoni until just al dente—you want a slight bite, as it will finish in the sauce. Reserve a cup of pasta water before draining.
Heat olive oil in a wide pan over medium heat. Add the minced garlic and cook gently for about 30 seconds until fragrant, keeping the heat controlled so it doesn’t brown.
Add the diced tomatoes with their juices and let them simmer for 5 minutes. This helps concentrate the flavor and slightly reduce the liquid.
In a blender, combine the cottage cheese with a small splash of pasta water and blend until completely smooth. This step ensures a creamy, cohesive sauce.
Lower the heat and pour the cottage cheese mixture into the pan. Add Italian seasoning, chili flakes, salt, and pepper. Stir gently and keep the heat low—avoid boiling to maintain a smooth texture.
Add the drained pasta to the sauce and toss well so it’s evenly coated. Use additional reserved pasta water as needed to loosen the sauce and help it cling to the pasta.
Stir in grated parmesan until melted, then finish with fresh parsley or basil. Taste and adjust seasoning before serving.