LAMB
2 heads garlic, peeled
1/4 cup extra-virgin olive oil
2 tablespoons fresh rosemary leaves
2 tablespoons rubbed sage
2 (2-pound) racks of lamb, frenched
1 tablespoon kosher salt
1 1/2 teaspoons black pepper
Flaky sea salt, to taste
GLAZE
3/4 cup packed light brown sugar
3/4 cup unsalted vegetable stock
2 tablespoons unsalted butter
1 1/2 tablespoons soy sauce
1 1/2 tablespoons Dijon mustard
1/2 teaspoon kosher salt
1/4 teaspoon ground nutmeg
1/4 teaspoon ground cinnamon
1 thyme sprig
1 rosemary sprig
2 tablespoons (1 ounce) gold rum
Combine garlic cloves, olive oil, rosemary, and sage in a food processor. Process until mixture is finely chopped, about 30 seconds, stopping to scrape sides of bowl as needed. Sprinkle lamb all over with kosher salt and pepper. Rub evenly with garlic mixture. Place lamb, fat side up, on an aluminum foil–lined rimmed baking sheet. Let stand at room temperature 45 minutes.
reheat oven to 450°F with oven rack in upper third of oven. Stir together brown sugar, vegetable stock, butter, soy sauce, Dijon, salt, nutmeg, cinnamon, thyme, and rosemary in a small saucepan. Bring to a boil over medium-high, stirring occasionally. Reduce heat to medium-low, and simmer, stirring occasionally, until mixture is syrupy and has reduced to about 2/3 cup, 25 to 30 minutes. Remove from heat. Remove and discard herb sprigs. Let cool 5 minutes, and stir in rum. Set aside.
Roast lamb in preheated oven until browned, 16 to 18 minutes. Remove from oven, and quickly brush tops and sides of lamb with about 1/4 cup glaze. Return to oven, and roast until lamb reaches desired degree of doneness, 5 to 8 minutes with an internal temperature of 125°F for medium-rare. Transfer lamb to a cutting board, and let rest 10 minutes.
Cut lamb between rib bones to separate into chops, and arrange on a serving platter. Sprinkle with flaky sea salt to taste. Drizzle with about 2 tablespoons glaze, and serve remaining glaze on the side.