Step 1

Heat the oven. Arrange a rack in the middle of the oven and heat the oven to 400°F.

Step 2

Make garlic paste. Cut off the stem end of the garlic cloves. Coarsely chop the garlic, then sprinkle with the salt. Hold the blunt side of the knife with both hands, angle the knife slightly, and scrape the pile of garlic and salt to flatten. Use the knife to create a small garlic and salt pile, then press and scrape again. Repeat this process a few more times until you have a smooth paste. Sprinkle the pepper over the paste.

Step 3

Trim the silverskin from the pork loin and rub with garlic paste. Trim the silverskin off of the pork loin, but leave the fat cap intact. Rub the garlic paste evenly over all sides of the pork loin. Set aside at room temperature for 30 minutes or refrigerate for up to 1 day.

Step 4

Brown the pork loin on all sides. Heat the oil in a 10- to 12-inch cast iron pan or stainless steel straight-sided skillet over medium-high heat until shimmering. Add the pork and sear on all sides until it's deep golden-brown and easily releases from the pan, 4 to 6 minutes per side. Once all 4 sides have browned, transfer the pork loin to a plate.

Step 5

Add the butter, onion, apples, and herbs to the pan. Turn off the heat, but keep the skillet on the stove. Scatter the apples, onion, butter, rosemary, and sage around the pan. Drizzle with the maple syrup.

Step 6

Return the pork loin and any juices to the pan. Nestle the browned pork loin on top of the onion, apples, and herbs, and pour in any accumulated juices from the plate.

Step 7

Roast the pork loin for 1 hour. Roast the pork loin until an instant-read thermometer inserted into the thickest part of the pork reads 145°F, about 1 hour. Meanwhile, make the green apple sauce.

Step 8

Make the green apple sauce while the pork roasts. Place the Granny Smith apple, lemon zest, lemon juice, garlic, mint, sage, parsley, rosemary, and salt in the bowl of a food processor fitted with the blade attachment. Pulse until finely chopped, 12 to 14 pulses, scraping down the sides of the bowl when necessary. Drizzle in the olive oil and pulse again until incorporated.

Step 9

Rest the pork loin for 20 minutes. Remove the pan from the oven and transfer the pork to a clean cutting board. Let the pork loin rest for 20 minutes.

Step 10

Slice the pork loin and serve with onion, apples, pan sauce, and green apple sauce. Slice the pork loin crosswise into 3/4-inch-thick slices. Serve the sliced pork with the onion and apple pieces. Drizzle with some of the pan drippings and the green apple sauce.