If desired, using a mortar and pestle, slightly crush coriander seed. Combine coriander seed, cumin, salt, sugar and chipotle chile powder in small bowl or dish; set aside.
Cut 4 long pieces of plastic wrap. Place 1 piece horizontally on work surface and the remaining 3 pieces vertically on the first piece. Place pork rack on center of plastic wrap. Sprinkle and rub spice mixture evenly over surface of pork rack. Wrap tightly in the plastic wrap. Place on a tray or shallow pan and refrigerate for 8 to 12 hours.
Pre-heat oven to 350° F. Unwrap pork and place on rack in shallow roasting pan with bones facing up. Roast in preheated oven for 1 to 1 1/2 hours (about 20 minutes per pound) or until internal temperature on a thermometer reads 145° F. Remove roast from oven. Loosely cover with foil and let rest about 10 minutes.
Carve between rib bones to serve. Serves 8.
Spoon pumpkin purée on plates and top with carved pork chops and cilantro salad; sprinkle with pepitas.
Nutritional information per serving when plated with Five-Spice Pumpkin Puree and Chile, Pumpkin Seed and Cilantro Salad.