Prepare the pasta according to the package instructions, ensuring it is al dente. Avoid overcooking for the best texture.
As the pasta cooks, blend the cheese sauce ingredients. Combine whole milk, cottage cheese, cornstarch, salt, garlic powder, pepper, cheddar cheese, and Pecorino Romano or Parmesan cheese in a blender. Blend on high until the mixture is completely smooth and creamy.
Once the pasta reaches al dente, drain it thoroughly but refrain from rinsing.
Return the drained pasta to the pot.
Pour the blended cheese sauce over the pasta, and heat on medium until the sauce is hot and silky.
Stir in the cooked pasta, ensuring each piece is evenly coated with the cheese sauce.
Allow any leftovers to cool fully before storing them in an airtight container in the refrigerator. They will keep for up to 4 days.