The problem with pork loin is that it is too lean and can be dry if you don’t gook it exactly right. I’ve tried a few things to keep it edible. One technique is to cut it in a spiral with a sharp filet knife, ending up with a long flat sheet of pork about 3/8" thick. Then create a stuffing of some kind. I have used sundried tomatoes, goat cheese and basil, but you could come up with any number of combinations. It should have lots of flavor and some moisture to it.
Slather the slab with the stuffing, roll it up and tie it. Brown it in dutch oven, with onions and garlic, add a braising liquid (wine , tomatoes, or chicken stock)and cook it slowly until the pork is done…I forget the temperature I shoot for but its usually lower than whatever my Polder thermometer reccommends.