Slice beef into thin strips against grain.
Chop cabbage into bite-sized pieces.
Mix cornstarch with beef strips thoroughly.
Heat oil in wok over high heat.
Add beef strips to hot wok.
Stir-fry beef for 3-4 minutes until browned.
Add garlic and ginger to wok.
Cook aromatics for 30 seconds only.
Add chopped cabbage to the wok.
Stir-fry cabbage for 2-3 minutes.
Pour soy sauce over the mixture.
Add sesame oil and season accordingly.
Toss everything together for 1 minute.
Serve hot immediately over rice.