Add the cornstarch and half the water to a small mixing bowl or glass measuring cup then whisk to combine. Add the remaining ingredients then stir with a fork or whisk to combine and set aside. Can be made up to 3 days ahead of time.
For the broccoli:
Place a steamer basket inside a medium-size pot over a couple inches of water. Add the broccoli to the basket then turn the heat to high. Once the water is boiling, place a lid on top, turn the heat down to low, then steam until the broccoli is tender, 5-7 minutes. Set aside.
For the stir fry:
Heat the sesame oil in a large wok or 12” skillet over high heat just until hot — do not burn the sesame oil. Once hot, add the chicken then spread it into an even layer in the bottom. Season with salt and pepper then let the chicken sit and sear undisturbed until golden brown on the bottoms, 1-2 minutes. Stir fry until the chicken is nearly cooked through, 2-3 more minutes.
Turn the heat down slightly then give the stir fry sauce another stir to ensure the cornstarch has not settled into the bottom of the bowl. Pour it in the the pan then stir with a spatula until the sauce has slightly thickened and reduced, 1-2 minutes, turning the heat down if necessary. Remove the pan from the heat.
Scoop cooked rice into bowls then top with the chicken and sauce, and broccoli then serve.
Video
Notes
In order to prevent soggy, overcooked broccoli, I like to serve the steamed broccoli on top of the chicken and sauce then have each person mix it all up in their own bowl before eating.