Coat beef in starch until well coated and fry in oil.
Fry beef until crispy, drain and set aside.
In the same oil used to fry the beef, cook garlic and ginger until fragrant.
Add remaining veggies and cook until tender.
Stir the sauce again to dissolve the cornstarch completely.
Add sauce to the pan and stir until it thickens a bit.
Add the beef pieces back and stir with the veggies and sauce.
Serve hot next to rice or noodles.