For marinade, combine sherry, 2tsp of the soy sauce, 2 tsp of the cornstarch and sesame oil in a large bowl; mix well. Add chicken and stir to coat well. Let stand 30 minutes.

Place black beans in a sieve and rinse under cold running water. Coarsely chop beans. Combine beans, ginger and garlic. Combine chicken broth, remaining soy sauce, oyster sauce and the remaining cornstarch in a small bowl; mix well and set aside.

Heat 2Tbsp of the vegetable or canola oil in a wok or large skillet over high heat. Add chicken and stir-fry until chicken turns opaque, about 3-5 minutes. Remove and set aside.

Heat remaining vegetable or canola oil in wok. Add asparagus and onion and stir-fry 30 seconds. Add water; cover and cook, stirring occasionally until asparagus is crisp-tender, about 4 minutes. Return chicken to wok.

Stir chicken broth mixture and add to wok; cook until sauce boils and thickens. Serve over brown rice.