Chef Layne is on the money. The other thing you should know is that most of the macaroni and cheese commercial products is made from powdered cheese and whey powder. And I always add a pinch of Nutmeg to Béchamel Sauce> When I served my apprenticeship in Europe that's the way I was taught(over 50 years ago)
In any event the pot being on the floor is no good , it should be put in The Freezer on top of a dishwashing rack so that cold air circulates around and under. Don't let health dept. see you put the pot on the floor it has to be 6 inches off the floor.
Don't know the one that you had but here is one I have used
ground shrimp, bread crumbs. dill, s&p tabasco,1 egg,chopped sautéed garlic ,parsley. shallots, chopped water chestnut. Mix all together stuff mushroom then dip in to Tempura batter and fry