Heat 3/4 cup milk in a large heavy saucepan over medium heat until steaming. Whisk together flour and the remaining 1/4 cup milk in a small bowl until smooth. Stir into the hot milk and cook, whisking, until the sauce is smooth and thick, about 2 minutes. Remove from heat and stir in the pureed cottage cheese, Cheddar cheese, nutmeg, cayenne, salt and pepper. Stir in the cooked macaroni. Spoon into the prepared baking dish. Sprinkle with Parmesan and breadcrumbs. Bake until bubbling and brown, about 35 minutes.