The beef with the soy sauce, sherry, sugar and sesame oil for at least 2 hours
marinate.
Chop the ginger and fry it briefly in a little oil with the spinach and then take it out of the pan again. Put some more oil in the same pan and fry the beef in it. Remove the meat from the pan again, mix the cornstarch and bouillon with the water and heat in the pan until the mixture simmers. Then add the spinach-ginger mixture, let it boil again briefly, then mix in the beef and fry everything again for about 1 minute while stirring.