Rinse black beans, drain and finely chop. Set aside with garlic.
In a liquid measuring cup measure chicken stock, soy sauce, Sherry, sugar and cornstarch. Whisk until combined. Set aside.
Heat oil in medium saucepan oven medium-high heat,
Add black beans and garlic. Stir for about 30 seconds.
Pour liquid into saucepan. Cook stirring continuously until sauce thickens, 2-4 minutes.
When cool pour into clean jar and label it. Keeps in refrigerator for several months. Makes about ¾ cup of sauce.