Bring a large pot of salted water to a boil. Cook pasta according to package directions.
Drain pasta, and prior to placing pasta back into the pot, place butter, PHILADELPHIA Cream Cheese and grated cheese into the pot. Pour drained pasta back into pot, onto ingredients. Add cut up slices of American Cheese, and approximately 1 cup of half and half or milk to the pot.
Return pot to stove and turn burner to low heat (using the same burner already used to cook the pasta works best as it will still be warm). Sprinkle in salt (and optional mix in items if using) and stir well. As cheeses start to melt, add an additional 1/2 cup of milk or half and half.
Continue stirring over low heat until all ingredients have melted and have combined with pasta. Add additional half and half or milk as needed to reach desired level of creaminess. Serve immediately and enjoy!