Boil the pasta: Bring a large pot of salted water to a boil. Cook pasta until just al dente according to package directions. Reserve 1/2 cup pasta water before draining.
Blend the sauce base: In a blender, add cottage cheese, Parmesan, garlic, olive oil, lemon juice, salt, and a few grinds of pepper.
Add 2 tablespoons hot pasta water and blend until completely smooth and creamy.
Adjust consistency: If the sauce is very thick, blend in another tablespoon or two of pasta water. You’re aiming for a pourable, velvety texture that will cling to noodles.
Warm it gently (optional): Return the drained pasta to the warm pot over low heat. Pour in the sauce and toss for 30–60 seconds until heated through. Do not boil the sauce—gentle heat keeps it silky.
Season and finish: Taste and add more salt, pepper, or lemon as needed.
Sprinkle red pepper flakes and fresh herbs if you like. Add a splash more pasta water if it tightens up.
Serve: Plate immediately with extra Parmesan on top. Enjoy while hot and glossy.