I don't remember where I got this recipe from, but made it again for NYE and it was pretty close to the porchetta I ate in Tuscany this fall. The leftovers are even better than the roast the first day.
1 T black peppercorns
2 t. fennel seeds
2 t. kosher salt
3 lb. pork loin
2 T. olive oil
4-5 cloves garlic, slivered
Grind pepper, fennel and salt into a fine powder. Set pork on a large sheet of plastic wrap. Rub powder all over meat. Make deep slits in pork and insert garlic slivers. Drizzle with olive oil and wrap with plastic. Let sit in the fridge for at least 2 hours. Place on a rack in the middle of the over and blast at 400 degrees for 15 minutes and then turn down the heat to 275 and cook for another 1.5 hours, or until 150 degrees in the middle.
Let rest at least 20 minutes and then slice as thinly as possible.