Combine salt and sugar in bowl. Using sharp knife, cut 1-inch crosshatch pattern about ¼ inch deep in fat cap of roast, being careful not to cut into meat.

Place roast on 2 large sheets of plastic wrap and rub salt mixture over entire roast and into slits. Wrap roast tightly with plastic. Place on large plate and refrigerate for 12 to 24 hours.

Adjust oven rack to lowest position and heat oven to 325 degrees. Line rimmed baking sheet with aluminum foil and set wire rack in prepared sheet.

Unwrap roast and place on rack. Cover sheet tightly with foil. Transfer to oven and cook for 2 hours.

Remove foil and continue to cook until meat registers 180 degrees in several places, 2½ to 3½ hours longer.

Combine honey, soy sauce, vinegar, pepper flakes, and five-spice powder in bowl.

Remove roast from oven. Brush top and sides of roast with ¼ cup honey mixture (set aside remainder).

Return roast to oven and continue to cook until meat registers 190 degrees and fork slips easily in and out of meat, 30 to 45 minutes longer.

Transfer roast to carving board and let rest for 1 hour.

Using boning or paring knife, cut around inverted T-shaped bone until it can be pulled free and removed from roast (use clean dish towel to grasp bone if necessary).

Brush pork with 2 tablespoons reserved honey mixture.

Using serrated knife, slice roast ½ inch thick. Drizzle with remaining honey mixture and serve.