My SECRET to a TENDER BEEF with BROCCOLI... Tender Yummy and Saucy!

Ingredients:
For the Beef Seasoning:
12oz of Beef (Sirloin, or flank, or clod steak)
1 tbsp cornstarch
1/2 tsp Baking Soda (my secret ingredient)
1 tsp Sesame Oil
1/2 tsp salt
1tbsp ShaoXing Cooking wine
1tsp soy sauce,
1/2 tsp black pepper
1-2 tbsp onion leeks
1 head of Brocolli
Garlic and ginger for sauteing
For the Sauce:
1/4c Beef broth (Lessen this if you dont like that much sauce)
1tbsp dark soy sauce
1tbsp soy sauce
1 1/2 tbsp Oyster sauce
1tbsp sugar
Slurry: (Pour this slowly until you get the consistency you prefer)
1 1/2 tbsp corn starch
1 1/2 tbsp water