Though this is a pretty straight forward recipe, traditionally, some dried mustard is added to enhance the cheesy goodness without tasting mustardy. A quarter teaspoon or so should do it. If you don't have dry, add a teaspoon of prepared mustard instead, doesn't matter which kind you have though grainy or whole seed versions may add an unwanted texture to the creaminess of the sauce.
Though this is a pretty straight forward recipe, traditionally, some dried mustard is added to enhance the cheesy goodness without tasting mustardy. A quarter teaspoon or so should do it. If you don't have dry, add a teaspoon of prepared mustard instead, doesn't matter which kind you have though grainy or whole seed versions may add an unwanted texture to the creaminess of the sauce.