Cook the pasta: Bring a large pot of salted water to a boil.
Add the macaroni and cook until just al dente according to package directions. Reserve 1/2 cup of pasta water, then drain and set aside.
Blend the creamy base: In a blender, add cottage cheese, Greek yogurt, broth, milk, whey protein, cornstarch, Dijon, garlic powder, onion powder, and a pinch of salt and pepper. Blend until completely smooth and silky.
Warm the sauce gently: Pour the blended mixture into the same pot over low heat.
Stir constantly for 2–3 minutes until it begins to thicken slightly. Do not let it boil.
Melt in the cheeses: Add the cheddar and Parmesan gradually, stirring until fully melted and smooth. If the sauce feels too thick, whisk in a splash of reserved pasta water to loosen.
Taste and adjust salt, pepper, and smoked paprika.
Combine with pasta: Add the cooked macaroni to the pot and stir to coat every piece. Keep heat low to avoid curdling. If needed, add another spoonful of pasta water for a glossy finish.
Serve or bake: Serve immediately as is, or transfer to a lightly greased baking dish, top with a tablespoon or two of panko, and bake at 400°F (200°C) for 8–10 minutes until lightly golden.
Finish and garnish: Sprinkle with chives or a dash of hot sauce.
Add steamed broccoli or peas for extra volume and fiber.