1. Preheat the oven to 350F. Lightly spray a 2-quart baking dish with nonstick cooking spray.
2. Bring 2 quarts water to a boil in a large saucepan. Add the macaroni and cook until tender, about 10 minutes; drain well.
3. Whisk the egg in a large bowl. Add the cottage cheese, sour cream, salt and pepper. Stir in the Cheddar. Fold in the macaroni and mix well. Spoon into the prepared baking dish.
4. Bake until bubbly and lightly browned, about 30 minutes. Sprinkle with the parsley.
Variation
For a bit of added crunch, top the baked casserole with a mixture of bread cubes and melted butter, then broil just until slightly browned.