Start to finish: 3 hours (1 hour active) / Servings: 8
This holiday-worthy roast was inspired by Argentinian matambre arrollado, or beef that is stuffed with hard-cooked eggs, vegetables and sliced cured meats, then poached or roasted. We opted for a boneless pork loin roast because its uniform shape makes it easy to cut into a ½- to ¾-inch-thick slab ideal for filling and rolling. Herbal, garlicky and subtly spicy chimichurri is the perfect accompaniment to the sweet, mild pork; we use some inside the roast, too. You’ll need a digital thermometer to test the roast for doneness. For convenience, the chimichurri can be made and refrigerated in an airtight container up to a day ahead.
The seasonings for the roast can be combined and stored at room temperature and the pork loin can be butterflied and refrigerated a day in advance, too. Additionally, the roast rests for 30 to 60 minutes after cooking, so your oven will be free for last-minute sides.
Don’t trim the fat off the pork loin. The fat cap lends richness to an otherwise lean cut and gives the roast an appealing burnished-brown appearance. Don’t rush when butterflying the pork loin. Short, small cuts allow for the best control so you can maintain an even slice and adjust as you go. Don’t worry if the surface of the butterflied meat is not perfectly flat or even; it won’t matter in the finished dish.
For the Chimichurri:
3 cups lightly packed fresh flat-leaf parsley
⅓ to ½ cup lightly packed fresh oregano
7 medium garlic cloves, smashed and peeled
1½ teaspoons ground cumin
1½ teaspoons ground coriander
¾ teaspoon red pepper flakes
Kosher salt and ground black pepper
¼ cup red wine vinegar
¾ cup extra-virgin olive oil
For the Roast:
1 tablespoon ground cumin
1 tablespoon ground coriander
2 teaspoons packed light brown sugar
Kosher salt and ground black pepper
4-pound boneless center-cut pork loin
6 ounces thinly sliced capicola or mortadella
½ cup pitted green olives, roughly chopped
1½ cups drained roasted red peppers, patted dry and torn into large pieces
⅓ cup panko breadcrumbs
3 hard-cooked large eggs, peeled and halved crosswise
1½ tablespoons extra-virgin olive oil
Flaky sea salt, to serve (optional)
1. To prepare the chimichurri, in a food processor, combine the parsley, oregano, garlic, cumin, coriander, pepper flakes, 1 teaspoon salt and ½ teaspoon black pepper. Process until finely chopped, 30 to 45 seconds. Scrape the bowl, add the vinegar and oil, then process until as smooth as possible, 45 to 60 seconds. Measure ¼ cup of the chimichurri into a small bowl and set aside; transfer the remainder to a serving bowl; cover and refrigerate until ready to serve.
2. To prepare the roast, heat the oven to 350°F with a rack in the lower-middle position. Line a rimmed baking sheet with foil, then fit with a wire rack. In a small bowl, stir together the cumin, coriander, brown sugar, 3½ teaspoons salt and 1½ teaspoons pepper. Set aside.
3. Cut eight 24-inch lengths of kitchen twine. Place the roast, fat side down, on a cutting board, positioning a short end facing you (see step-by-step photographs here ). With a sharp boning or carving knife, cut along the length of the roast, slicing down its center, stopping about ½ inch from cutting through the roast.
4. Starting at the base of the cut and with the knife blade held as parallel as possible to the cutting board, slice along one side of the roast, unrolling the meat with your free hand as you go. Continue cutting and opening up the meat until the half is a flat, fairly even surface ½ to ¾ inch thick. Rotate the roast 180 degrees and repeat with the second side. If there are areas that are slightly too thick, use a meat mallet to pound those spots to the same thickness.
5. Season the pork on both sides with the spice mixture. Place the meat fat side down and with a short side nearest you. Spread the reserved ¼ cup chimichurri evenly on the meat. Shingle on the capicola slices, covering the entire surface, then sprinkle evenly with the olives. Lay the red peppers on top, tearing them as needed to cover the entire surface. Sprinkle the filling evenly with the panko. Place the egg halves cut sides down in a row about 3 inches from the bottom edge.
6. Lift the bottom edge of the roast over the eggs and slowly roll the meat into a tight cylinder. Position the cylinder seam side down and tie at even intervals with the twine, then snip off excess twine. If any bits of filling fall out, simply tuck them back in at the ends. Brush the roast on all sides with the oil.
7. Transfer the roast fat side up to the prepared baking sheet. Bake until the top is nicely browned and the center of the roast reaches 135°F, 1½ to 2 hours. Let rest on the wire rack for 30 to 60 minutes.
8. Remove the chimichurri from the refrigerator about 30 minutes before serving. Cut the roast into ½-inch-thick slices, removing the twine as you go. Arrange the slices on a platter, sprinkle with flaky salt (if using) and serve with the remaining chimichurri on the side.