Begin by bringing a large pot of salted water to a boil. Add in the elbow macaroni and cook according to the package directions until al dente. Once cooked, drain the macaroni in a colander and set aside.
In a mixing bowl, combine the cottage cheese, shredded cheddar cheese, non-fat milk, cornstarch, protein powder (if using), salt, and pepper. Use a whisk to mix everything together until smooth and creamy.
In the same pot you used for the macaroni, return the drained pasta and pour the cheese sauce over it. Stir everything together over low heat, allowing the cheese to melt and coat the pasta thoroughly.
You can serve the Protein Mac And Cheese straight from the pot or transfer it to an oven-safe dish and bake at 350°F for about 15 minutes for a crispy top.
