In a small bowl, whisk together the soy sauce, honey, garlic, ginger, and cornstarch. Set aside.
Add the sesame oil to a large deep skillet over medium-high heat. Add the beef and onion and cook, stirring occasionally, until the meat is just about cooked through, about 5 minutes.
Pour in the reserved sauce, stir to combine, and cook for 1 minute. Add the broccoli and cook for 1 more minute.
Divide mixture evenly among 4 plates or shallow bowls, layering rice first, if using.
Top each with sesame seeds and scallions.