**Update- Sept. 14, 2015: After intense re-testing, we've updated the recipe to boil the pasta in some water first, which will reduce the gummy/sticky results that some readers are getting. Then the milk is added afterwards to finish boiling/cooking and the results are even better!
The input and advice from reader comments are extremely valuable. Technique is very vital to making this recipe a success, as well as the type of ingredients, milk, cheese & macaroni that you use.
The key to keeping this recipe creamy is to make sure the flame is low and to consistently stir the pot. We use the smaller size of mac elbows and they need to be cooked slowly in the water, then the milk. Medium to High heat will cause the milk to burn. Don't leave the pot unattended.
Obviously with the stove top, there won't be that cheesy crust that forms on top. But toppings of toasted bread crumbs or bacon should be a nice exchange.