Asian Sauce for Pork

Asian Sauce
5 tablespoons Homemade Chicken Stock
1 tablespoon oyster sauce
2 1/2 teaspoons sugar
2 1/4 teaspoons tapioca starch
2 teaspoons ketchup
1 1/2 teaspoons dark soy sauce
Pinch freshly ground white pepper
1 tablespoon peanut oil
1 small onion, cut into 1/4-inch pieces
3/4 cup Asian Barbecued Pork
1 1/2 teaspoons Chinese rice wine or gin
1 teaspoon toasted sesame oil