Brine the pork
In a 3- to 4-quart saucepan, combine the salt, sugar, garlic, and herb sprigs with 2 cups of water. Stir over high heat just until the salt and sugar dissolve. Add 6 more cups of water and cool to room temperature. Transfer to a large container, add the pork, cover, and refrigerate for 8 to 18 hours.
Make the herb paste
Put the garlic, rosemary, sage, 1 Tbs. salt, and 1 tsp. pepper in a large mortar and pound to a coarse paste with the pestle. Add the oil and use the pestle to work it into the garlic paste. If you don’t have a mortar and pestle, combine all the ingredients in a mini food processor and pulse into a coarse paste.
Butterfly and season the pork
Remove the pork from the brine and pat it dry (discard the brine). Butterfly the pork loin by making a horizontal slit down the length of the loin, cutting almost through to the other side. Open the meat like a book. Spread half of the herb paste over the inner surface of the roast; then fold it back to its original shape. Tie the roast at 1-inch intervals with butcher’s twine and then spread the remaining herb paste over the entire outer surface.
Grill the pork
Set up a grill for indirect rotisserie cooking according to the manufacturer’s instructions. Heat the grill to 350°F. When ready to cook, skewer the roast lengthwise on the rotisserie spit and let it rotate on the grill, covered, until an instant-read thermometer inserted near the center of the roast registers 145°F, 35 to 45 minutes.
If you don’t have a rotisserie, set up your grill for indirect grilling. Heat the grill to 350°F. Put the roast in the cool zone on the grill, and cook as directed above, turning the roast about every 10 minutes.
Remove the roast from the spit if necessary and transfer it to a cutting board. Let stand for 5 minutes, remove the string, and slice thinly. Serve hot, warm, or at room temperature.
Make Ahead Tips
The pork must be brined 8 to 18 hours ahead. You can also butterfly and season the roast with the herb paste up to 4 hours before grilling. Refrigerate, but let sit at room temperature while you heat the grill.
nutrition information (per serving):
Photo: Scott Phillips