1 teaspoon whole black peppercorns, plus freshly ground black pepper, for seasoning
6 whole cloves
4 allspice berries
3 juniper berries
1/3 cup kosher salt, plus more for seasoning
2 cups apple cider
1/2 cup pure Grade A dark amber maple syrup
1/3 cup maple sugar (See Note)
6 garlic cloves, peeled
6 thyme sprigs
Four 1 1/4-pound pork tenderloins
1/4 cup canola oil
In a medium saucepan, toast the 1 teaspoon of black peppercorns with the cloves, allspice and juniper over moderate heat until fragrant, 2 minutes. Add the 1/3 cup of salt and the apple cider, syrup, sugar, garlic and thyme to the saucepan and bring just to a simmer, stirring. Add 3 cups of cold water and pour the brine into a small roasting pan; let cool. Add the pork tenderloins, cover and refrigerate for 6 to 8 hours.
Preheat the oven to 350°. Drain the pork, discarding the brine. Pat the pork dry and season lightly with salt and pepper. In a very large skillet, heat 2 tablespoons of the canola oil until shimmering. Add 2 of the pork tenderloins and cook over moderately high heat, turning, until browned all over, about 8 minutes. Transfer the pork to a rimmed baking sheet. Wipe out the skillet and repeat with the remaining 2 tablespoons of oil and 2 tenderloins.
Transfer the pork to the oven and roast for about 18 minutes, turning twice, until an instant-read thermometer inserted in the thickest part of the meat registers 140°. Transfer the pork to a cutting board and let rest for 10 minutes. Slice the pork and serve.
NOTES Granulated maple sugar, which is made from reduced maple syrup, is avail-able at specialty food stores or online at crownmaple.com.