Beef and Broccoli with the Best Sauce

Ingredients

Beef and Broccoli Ingredients:
1 lb flank steak, very thinly sliced into bite-sized strips
2 Tbsp olive oil , (or vegetable oil), divided
1 lb broccoli, (cut into 6 cups of florets)
2 tsp sesame seeds, optional garnish
Stir Fry Sauce Ingredients:
1 tsp fresh ginger, grated (loosely packed)
2 tsp garlic, grated (from 3 cloves)
1/2 cup hot water
6 Tbsp low sodium soy sauce, (or GF Tamari)
3 Tbsp packed light brown sugar
1 1/2 Tbsp corn starch
1/4 tsp black pepper
2 Tbsp sesame oil