Prepare the pork by scoring the skin with the tip of a sharp knife, creating straight lines parallel to one another about 2 inches apart. Repeat on the diagonal so they criss cross. Flip the pork middle over and repeat on the meat side.
Toast the fennel seeds and red pepper flakes for about 1-2 minutes on medium heat in a dry skillet. Let it cool. Finely grind the cooled spices in a food mill or blender and set aside.
Finely mince the garlic, along with the fresh herbs. Combine this mixture with the lemon zest, ground fennel and red pepper flakes, along with 1 tablespoon of salt. Season the meat liberally.
Roll the pork beginning with the loin portion, seasoning the skin along the way with a little salt. Use butcher’s twine to secure the roast by tying it crosswise in 2-3 inch intervals. Season the skin with the remaining salt.
Let the roast rest in the refrigerator, without any cover, ideally overnight. Pat dry with paper towels periodically. This will help with crisping the skin.
When you are ready to roast, let the roast sit for about 1 1/2-2 hours at room temperature. Place in a roasting pan with a rack.
Preheat the oven to 412° F with the oven rack in the center of the oven.
Place the roast in the oven and roast for about 2 hours, or until a thermometer inserted in the center of the roast reads 145 degrees. About 15 minutes prior to finishing, if the skin is not bronzed, increase the temperature to 450° F degrees for the final moments of cooking.
Remove the roast from the oven and let it rest for 30 minutes. Slice into rounds about 1/2 inch thick using a serrated knife.
Special thanks to Christian Shiflett at Avedano's for his guidance in roasting porchetta. This recipe also contains adaptations from from Porchetta, Bon Appetit (September, 2011) and Rabbit Porchetta, In the Charcuterie by Taylor Boetticher and Toponia Miller (Ten Speed Press, 2013).