I'm not a huge fan of mac and cheese but this stuff is really good. I have made it many times and the last few times I have been tweaking it.
This is the basic recipe:
2 cups dried pasta
2½ cups milk
1 cup shredded cheese
4 oz. cream cheese
1/2 tsp. salt
1 tsp. Dijon mustard
In a small saucepan, add pasta and milk. Bring to simmer, then reduce heat to low and cook for 20 minutes, until pasta is soft, stirring frequently and ensuring milk does not boil. Preheat oven to 375 degrees. Turn heat off, add cheese, salt and stir to combine. Stir in the mustard a little at a time to taste. Cover and let stand for about 5 minutes, then stir again and serve. If not creamy enough, add milk a little at a time, and gently stir. If you would like to bake it at this point, place in a baking dish and top with a generous sprinkling of cheese. Bake for approximately 10 minutes until cheese has melted.
NOTE: I never bake it in the oven and I also don't turn off the heat when adding the cheese, I just turn it down.
Tweak 1: I added 6 oz of cream cheese instead of 4. Good but almost too creamy.
Tweak 2: I have started doing a heaping tsp of mustard. I do the regular amounts of everything but I have added two oz of Velveeta cheese. It gave a little more of a cheesy flavor and added nice texture.