RIBS WITH BLACK VINEGAR SAUCE

2 lbs. pork spareribs, cut into individual ribs
¼ cup cornstarch
About 12 cups peanut or vegetable oil for frying, divided
4 garlic cloves, thinly sliced
1 medium shallots, thinly sliced
2 tbsp. very thin matchsticks of peeled ginger
½ cup packed light brown sugar
2 tbsp. Chinese Shaoxing wine or medium-dry sherry
½ cup reduced-sodium chicken broth
½ cup Chinese black vinegar
½ cup reduced-sodium soy sauce
Equipment: a deep–fat thermometer
Blanch ribs in a 4-quart pot of boiling water 4 minutes. Drain and pat dry