Cook the pasta. Bring a large pot of salted water to a boil. Add pasta and cook until just shy of al dente, about 1–2 minutes less than the package suggests. Reserve 1/2 cup pasta water, then drain.

Blend the base. In a blender, combine cottage cheese, Greek yogurt, milk, Dijon, garlic powder, onion powder, and paprika. Blend until completely smooth and silky.

Stabilize the sauce. In a small bowl, whisk cornstarch with 1 tablespoon water to make a slurry. This helps prevent a grainy or watery sauce.

Build the cheese sauce. Melt butter in a large skillet over medium heat. Pour in the blended mixture and the cornstarch slurry. Cook, whisking gently, until it starts to steam and thicken, 2–3 minutes. Do not let it boil hard.

Add the cheeses. Reduce heat to low. Stir in cheddar and Parmesan by the handful, letting each addition melt before adding more. Season with salt and pepper. If it seems too thick, loosen with a splash of milk or reserved pasta water.

Combine with pasta. Add drained pasta to the skillet and toss to coat. Let it simmer on low for 1–2 minutes so the noodles absorb the sauce. Adjust seasoning as needed.

Finish and serve. Top with chives, a dash of hot sauce, or toasted breadcrumbs if you like. Serve hot and enjoy that creamy, cheesy pull.