First attempt at a butterflied pork loin -> mock porchetta. Starting at the top/fatty edge, sliced through to within a third inch of the opposite edge, reverse, do again, until you have a flat piece of meat. Stomp down any thick ridges.
Spread with a garlic/herb/evoo combination of your choice
Roll tightly and tie, keeping the fat layer outside. Start in the middle first and work to the ends.
Lay on bed of onion or shallot
Surround with potato or aromatics.
Roast as size suggests. Let rest and slice thinly.
Serve with pan juices. Cold, thinly sliced leftovers may even be better.