Brining time: 12 to 24 hours

Prep time: 15 minutes

Cook time: 1¼ hours

In summer, when big bunches of fresh basil are sold everywhere, take advantage of the bounty and make batches of pesto. Classic pesto is typically made with basil, pine nuts, and pecorino romano cheese, but this adaptation is made with walnuts and Parmesan cheese and is slathered in the center and on top of the pork roast. Because the loin is lean, brining is recommended for 12 to 24 hours before roasting.

Walnut Pesto: One day before roasting the pork, make the brine: In a large bowl, dissolve the salt in the hot water. Add the cold water and the ice cubes. Place the pork in a large, heavy-duty resealable plastic bag. Add the brine and seal the bag closed. Seal it in a second plastic bag for reinforcement. (Or, use any large container and cover it tightly.) Place on a rimmed sheet pan and refrigerate for 12 to 24 hours. When ready to cook, drain the brining liquid and discard, and then wipe the roast dry with paper towels. Let stand at room temperature for 30 minutes before roasting.

Meanwhile, make the pesto: In blender or food processor, combine the basil, ½ cup of the oil, and the walnuts, garlic, salt, and pepper, and process until finely chopped. With the motor running, slowly add the remaining ½ cup of olive oil and process until the mixture is well blended. Be careful not to overprocess the pesto. You should be able to see small pieces of basil throughout. Transfer the pesto to a small bowl and stir in the cheese.

Preheat the oven to 400°F. Have ready a large roasting pan with a rack. Cut 8 pieces of cooking string each about 18 inches long, or have ready silicone ties. Place the pork loin on a cutting board and butterfly it by making a slit along the side from the top to the bottom, cutting just deep enough so that the loin opens up and lies flat like a book. Using a thin, flat metal spatula or a narrow rubber spatula, slather the cut surface with about ½ cup of the pesto. Fold it over and tie firmly, but not too tightly, at 1- inch intervals with the lengths of string or the ties.

Place the tied loin on the rack in the roasting pan. Roast for 45 minutes. Remove the pan from the oven and slather about ¼ cup of the remaining pesto on top of the roast. Continue roasting for 30 minutes longer, or until an instant-read thermometer registers 135°F. Remove from the oven and let rest for 10 minutes. As the pork rests, the internal temperature will rise to 145°F, or medium-rare.

Using 2 broad spatulas, lift the roast from the rack to a cutting board. Snip off the strings, or remove the silicone ties. Cut the pork into ½-inch-thick slices. Arrange the slices, overlapping them, on a large platter. Drizzle any juices from the cutting board over the meat. Serve warm or at room temperature. Pass the remaining pesto at the table.