A tiny bit more work than using a prepared black bean sauce in a jar, but well worth it. Sauté a tablespoon or two of salted (AKA fermented) black beans, a clove or two of minced garlic and a couple of teaspoons of shredded fresh ginger in hot peanut oil for a few seconds 'til fragrant, then build your stir fry as you like it. A terrific, authentic, and more economical. Also great atop fish when steaming.