In a small bowl combine Hoisin sauce, brown sugar, honey, soy sauce, dry sherry, oyster sauce, five spice, garlic and red food coloring (optional) and mix until combined.
Cut pork horizontally into three long flat pieces. Place in a container or ziplock bag, pour ½ the marinade over pork. Marinade 24-48 hours for optimal flavor.
Preheat oven to 350 degrees. Cover a baking sheet with foil and place a cooling rack on top. Remove pork from the marinade and place on the rack. Bake for 25 minutes. Flip the pork and cook another 25 minutes.
While the pork is cooking, pour the reserved marinade into a saucepan and whisk in cornstarch, and bring to a low simmer for 10 minutes to thicken.
Remove pork from the oven and turn the oven to broil. Brush the pork with the thickened marinade and broil 5-6 minutes or until slightly charred. Turn the pork over and repeat. Pork temp should be 145-160 degrees.
Serve any extra sauce on the side, and green onions if desired.
