Boil a large pot of water with a dash of salt in it. Put pasta into the boiling pot of water and cook until al dente or about 7 minutes.
Set oven temperature to 400�F. Using the cooking spray, grease a 2 quart casserole dish.
Blend the cottage cheese using a food processor until it is smooth. Add the cottage cheese, egg white, sweetener, cheese cubes, and buttermilk into a large bowl and stir. Mix the pasta into the large bowl.
Pour the macaroni and cheese into the casserole dish and sprinkle the saltines on top.
Bake the macaroni and cheese for 30 minutes.