Night before: Pat the lamb rack completely dry with paper towels. Score the fat cap in a shallow crosshatch pattern — cut just through the fat, not into the meat. Season the meat side only with the kosher salt, avoiding the fat cap. Place on a wire rack set over a sheet pan, uncovered, in the refrigerator overnight.

Morning: Combine the doubanjiang, Shaoxing wine, dark soy sauce, toasted sesame oil, honey, garlic, ginger, cumin, five-spice powder, and ground Sichuan peppercorn in a bowl. Mix into a thick, paintable paste.

Paint the paste generously over the rack's meat side and fat cap, pressing it into the score marks. Wrap exposed bone tips in foil. Return to the wire rack set over a sheet pan, uncovered, in the refrigerator for the rest of the day.

Evening: Remove the rack from the refrigerator 45 minutes before cooking to take the chill off. Preheat oven to 400°F.

Heat the neutral oil in a cast iron skillet over high heat until smoking. Place the rack fat-side down with the paste on and sear until the fat renders and the paste takes on color, about 2 minutes. Flip and sear the meat side for about 1 minute.

With the rack fat-side up in the skillet, transfer directly to the 400°F oven. Roast until internal temperature reaches 130°F for medium-rare, roughly 15-20 minutes.

While the rack rests, toast the whole Sichuan peppercorns in a small dry skillet over medium-low heat, shaking frequently, until fragrant and slightly darkened. Transfer to a mortar or spice grinder and grind fine.

Set the cast iron skillet over medium heat. Deglaze with the Shaoxing wine, scraping up the fond. Add the chicken stock and bring to a simmer. Stir in the doubanjiang and Chinkiang black vinegar. Reduce by about half, then remove from heat and swirl in the cold butter until emulsified. Strain through a fine mesh strainer.

Slice the rack into individual or double chops. Spoon the pan sauce over or alongside. Finish with the sliced scallion greens, toasted sesame seeds, and a pinch of the freshly ground Sichuan peppercorn.