Put pork belly cubes in a 4- to 5-quart slow cooker. Whisk soy sauce, sherry, water, brown sugar, vinegar, ginger, garlic and five-spice and pour around the meat.

Cover and cook on low for 6 to 7 hours until the meat layers yield easily to a fork and the pork is at least 145°F, generally nearer 190°F when fully tender. Lift cubes gently with a slotted spoon.

Arrange pork on a rack over a foil-lined broiler-safe pan. Pour cooking liquid into a saucepan, remove the garlic and skim off the generous rendered-fat layer.

Simmer the skimmed liquid for 8 to 12 minutes until reduced to about 1/2 cup. Brush a thin layer over the pork and broil 6 inches from the heat for 3 to 5 minutes, turning carefully once, until the edges brown.

Rest for at least 3 minutes and serve the intact layered cubes with a small amount of remaining glaze.