Project Description

Pork Loin Roast with Roasted Potatoes, Fennel and Red Onions

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4-6 Servings
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Difficulty Level
Active Prep
Active Prep
30 min
Total Time
Total Time
1 hour 40 minutes (plus marinating)

We’re doing a play on porchetta, using the same flavors. We’re skipping the pork belly, though, and adding mortadella to bring some juiciness to the lean loin. This is a showstopper of a dish, so make sure there are plenty of people there to tell you how amazing you are when you carve into it. Get your butcher to butterfly the pork loin. There are two ways to butterfly the loin, either opening it as a book, or unrolling it like a roll of paper towels. We’re using the unrolling method to get that very cool swirly effect when it’s sliced. If the butcher has no idea what you’re talking about, don’t let him touch it. Take it home and do it yourself with the easy instructions here. Then find a new butcher.

See Cook’s Note on how to butterfly a pork loin.


for the pork

Line a rimmed baking sheet with foil and set a rack on top.

Toast the fennel seeds in a small, dry skillet over medium heat until fragrant, keeping the seeds moving to prevent them from burning, 3 or 4 minutes. Remove them to a plate and allow them to cool, then grind them in a mortar and pestle or spice grinder. Combine the ground fennel seed, garlic, oil, zest, pepper flakes and rosemary in a small bowl to form a paste. Unroll the butterflied pork loin and rub all over with a generous amount of salt and pepper. Place the loin on a clean surface so that the fat side is facing down and the meaty side is facing up. Rub the spice mixture all over the meaty side, then line with a shingled layer of the mortadella. Roll tightly, with fat cap on top, and tie with kitchen twine. Place the roast on the prepared baking sheet and refrigerate, uncovered, for 8 hours or overnight.

Let the roast sit at room temperature for at least 30 minutes before cooking.

Preheat the oven to 400 degrees.

for the glaze

Combine the marmalade and mustard in a small bowl. Set aside.

for the veggies

Remove the pork to a platter or cutting board. Give the foil a quick wipe if there’s blood on it. Lightly grease the foil. Spread the potatoes, onions, and fennel in a single layer on the baking sheet. Drizzle with oil and season generously with salt and pepper. Toss and spread out again on the pan.

Place the pork loin fat side up on top of the vegetables and roast for 40 minutes. Give the vegetables a stir, then slather the glaze over the top, sides and ends of the loin. Continue to roast until the glaze is nicely browned, 15 to 30 minutes more, depending on the shape of the pork. The most important indicator will be the internal temperature of 140 degrees. Transfer to a cutting board and let rest at least 10 to 15 minutes before slicing. Return the vegetables to the oven if needed (some of the larger pieces may still need some time). Serve with the roasted vegetables.

You should get your butcher to butterfly your pork loin, but it’s really pretty easy to do it yourself. Just flip the loin over so that the fat side is on the board and the meaty side is up. Hold your knife parallel to the cutting board and starting about an inch up the side of the loin, make a long, even slice along the length of the meat. Begin unrolling the meat as you cut it, then follow with another slice so you can unroll it some more. Continue until you’re left with a reasonably flat piece of pork on the cutting board. If it seems uneven, use a meat mallet to flatten it out.



  • 2 tablespoons fennel seeds
  • 4 cloves garlic, finely chopped or grated
  • 2 tablespoons olive oil
  • 1 tablespoon finely grated fresh orange zest (from 1 orange)
  • 1 teaspoon crushed red pepper flakes
  • 3/4 teaspoon finely chopped fresh rosemary
  • 3 pound boneless, center-cut pork loin with some fat cap left on, butterflied
  • Salt and freshly ground black pepper
  • 3 ounces mortadella, thinly sliced


  • 1/2 cup orange marmalade, preferably without thinly sliced rind, or apricot preserves
  • 3 teaspoons dry mustard


  • 1 pound red new potatoes, scrubbed and dried, halved
  • 1 fennel bulb, trimmed, cut into 3/4-inch wide wedges with the cores intact
  • 1 large red onion, cut into 1-inch wide wedges with the cores intact
  • 2 tablespoons extra-virgin olive oil, plus additional for greasing
  • Salt and freshly ground black pepper

special equipment

  • mortar and pestle or spice grinder, kitchen twine, rack and foil-lined rimmed baking sheet


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