First make the sticky sesame sauce: Whisk together cornstarch and water mixture in a small bowl. In a medium saucepan, add all of the sesame sauce ingredients along with the cornstarch/water mixture. Stirring frequently, bring sauce to a simmer. Cook until sauce thickens and darkens, about 5-7 minutes. Remove from heat.
Steam Broccoli for about 5-7 minutes, until tender but firm. Remove from heat and set aside.
Pat chicken dry and season with salt, garlic powder and pepper on all sides. Sprinkle with cornstarch and toss to fully coat the chicken. Pour beaten egg over chicken and toss to combine.
In a skillet or wok over high heat, add oil. Once the oil is hot, carefully add the chicken. Stir fry the chicken for about 8-10 minutes until the chicken is golden and cooked through. Add broccoli and stir fry an additional 2-3 minutes.
Add the sticky sesame sauce to the chicken and toss to combine. Cook for 1 more minute and then remove from heat.
Serve sesame chicken and broccoli over white rice and sprinkle with sesame seeds. Enjoy!