Sprinkle sirloin with salt and toss with cornstarch until well coated.
In a 9″ cast iron pan, heat coconut oil over high heat.
Cook sirloin strips in batches until golden brown, then transfer to a paper towel-lined plate.
Pour off excess oil from the pan, retaining a few fried bits for flavor.
Add brown sugar and orange juice to the pan, whisking over medium-high heat until thickened.
Whisk in soy sauce, chili garlic sauce, and orange zest.
Toss in the cooked beef and broccoli florets, stirring until the broccoli is tender.
Serve over sticky rice, if desired.