Preheat your oven to 375°F (190°C).
Butterfly the pork loin by slicing it lengthwise, being careful not to cut all the way through.
In a bowl, mix breadcrumbs, Parmesan cheese, garlic, parsley, salt, and pepper.
Spread the mixture evenly over the inside of the pork loin.
Roll up the pork loin and tie it with kitchen twine.
Heat olive oil in a pan and sear the pork loin on all sides until browned.
Transfer the pork loin to a baking dish and roast in the oven for about 60 minutes, or until the internal temperature reaches 145°F (63°C).
Let the pork loin rest for 10 minutes before slicing and serving.