Put the pancetta in the bowl of a food processor and pulse until it forms a paste. Transfer to a bowl and mix in by hand the garlic, citrus zests, parsley, rosemary, red pepper flakes, capers and 2 tablespoons salt until thoroughly blended.
Put the ham flesh-side up on a cutting board and score the meat with the tip of a sharp knife every inch or so in a cross-hatch pattern. Rub the pancetta paste into the meat, making sure to get it into the score marks. Flip the ham over and score the skin with the knife as you did the flesh. Roll the ham up skin-side out and secure with kitchen twine. Season the skin lightly with salt.
Put the pork in a roasting pan and transfer to the oven to roast for 2 hours.
Increase the oven temperature to 400 degrees F and roast until the pork reaches an internal temperature of 170 degrees F and the skin is nice and crisp, about 1 hour, 30 minutes.
Remove from the oven and let rest for 30 minutes. Thinly slice the porchetta before serving.
Photograph by Yunhee Kim
Recipe courtesy Michael Symon for Food Network Magazine