Sweet-and-Sour Sauce

My mother used to make this by the gallon for her catering business in our tiny basement in Minneapolis. On Saturday mornings, we would wake up not to the whiff of pancakes, but to the aroma of dark soy sauce, crushed pineapple and vinegar melding together to make this perfectly balanced dipping sauce that’s just the right amount of sweet and just the right amount of sour. I always say life wouldn’t be as sweet without the sour! This versatile sauce, also known as duck sauce or plum sauce,