Aged cheese?

All hard and most semi hard cheeses are aged to around a year or more which should be enough. I think you will find the deli section of most stores sells "specialty cheeses" which are just brand name cheeses that have been aged. The exception to this is many chains have their own "store Brand" cheeses which are usually younger and not what you want. Also check for cheeses with a low sugar content (5 grams or less) and it will have less lactose as well.