This is one of those family recipes that has evolved over the span of my lifetime. I first learned to cook this when I was a preteen. It continued to tweak it during my married life. I had some leftover Gouda in the fridge and decided to add it. Since then, it has become my picky kids favorite. In our house this is the main meal.
Serve with a green salad, steamed broccoli and garlic toast or crusty sour dough bread.
EDIT TO ADD 4/2012: if doubling this recipe, use only 5 tablespoons of flour and 6 cups of milk. If you do not, you run the risk of a not so creamy and somewhat dry end result. I have also added a bit more milk because the under cooked macaroni will absorb some of the milk. Feel free to add more American cheese. The amounts can be increased to your liking.