Cantonese Tomato & Beef Stir Fry

0 Add beef, water, baking soda and olive oil together into a bowl to marinate for 30 minutes.
1 Slice onions and tomatoes, then mix together sauce ingredients. 
2 Preheat pan to medium heat with oil to cook beef and sear until cooked through. Remove from pan! 
3 Add more oil to pan and add in onions to cook until softened, about 2-3 minutes. Add beef pieces back in along with tomatoes and sauce poured in to mix. Cook until sauce thickens and serve warm with rice!