Place vegetable oil in a small pot and heat over medium-high heat until it reaches 350 degrees. Add chopped plantains and fry until golden brown, about 1 minute. Transfer to a paper-towel-lined plate; set aside.
Heat a medium skillet over medium-high heat. Add longaniza and cook, stirring, until cooked through. Remove from heat and set aside.
Place pork loin on a cutting board. Cut pork loin lengthwise, stopping about 1 inch from the opposite end. Open pork loin like a book and pound using meat mallet until it is 1/3-inch-thick. Transfer pork loin to a baking dish and cover with brine solution. Refrigerate at least 20 minutes or up to 40 minutes.
In a large bowl, combine fried plantains, longaniza, scallions, and cilantro; toss to combine. Add sweet plantain mash and mix thoroughly. Place half of the plantain mixture in the center of a 12-by-12-inch piece of plastic wrap and roll tightly like a cigar; twist ends to enclose.
Remove pork loin from brine and place on a parchment-paper-lined cutting board with the long side of the pork loin facing you. Unroll filling and place on the edge closest to you; roll pork loin away from you, like a jelly roll. Using kitchen twine, tie pork loin in 1 1/2-inch intervals to retain its shape. Wrap tenderloin with plastic wrap and refrigerate for 15 minutes.
Preheat oven to 500 degrees. Coat the bottom of a large ovenproof skillet with olive oil and place over high heat. Unwrap tenderloin and season with salt and pepper. Add to skillet and cook, turning frequently, until well browned, about 5 minutes. Transfer skillet to oven and roast for 45 minutes. Add butter, garlic, and oregano to pork loin and continue to roast, basting occasionally, until a thermometer inserted into pork reads 165 degrees, about 2 minutes more.
Transfer pork loin to a platter and let stand 10 minutes. Remove kitchen twine and cut pork loin crosswise into 1 1/2-inch-thick slices. Serve with and remaining plantain mixture and sour orange gastrique.
Save to your Collections
Sorry for the inconvenience! Saving is temporarily unavailable as we work through a few kinks in our new recipe design (we hope you like it!). Don't worry, your collections are safe and you'll be able to save recipes again very soon.
Review this Recipe
Reviewing recipes is temporarily unavailable as we work through a few kinks in our new recipe design. You'll be able to comment again soon. Sorry for the inconvenience!