Taste the sauce and add more salt and seasoned salt as needed! DO NOT UNDERSALT. Pour in the drained, cooked macaroni and stir to combine. Cook for a few minutes stirring constantly. Cheese Sauce: In 4-quart saucepan make roux: melt butter and stir in flour, white pepper, mustard and salt until smooth.
Set a large pot (6-quart or larger) of salted water (1 tablespoon salt) to boil. Stir until smooth. Add in the cheese and stir to melt. Add the salt, seasoned salt and pepper. Butter pan and preheat oven to 350 degrees F.
Cook the cavatappi pasta in boiling salted water per the instructions on the box, until al dente. The macaroni should be too firm to eat right out of the pot. Spray a 13 x 9 inch baking dish with butter flavored cooking spray.