In a small bowl, dissolve the cornstarch in ¼ cup of cold water, stirring until smooth and no lumps remain. Set aside for later use.
In a small saucepan, combine the soy sauce, 1 cup of water, ground ginger, garlic powder, brown sugar, and honey. Place the saucepan over medium heat and allow the mixture to warm up.
Once the sauce starts to simmer, slowly pour in the cornstarch mixture, whisking constantly until the sauce thickens. This process usually takes about 3 to 5 minutes. Once thickened, remove from heat and set aside.
Preheat your oven to 400°F. Line a 9x13-inch baking sheet with parchment paper for easy cleanup.
Cut the chicken breasts into 1-inch bite-sized pieces and arrange them on one half of the prepared baking sheet.
Cut the red bell pepper and purple onion into 1-inch slices. Arrange these along with the broccoli florets on the other half of the baking sheet. Drizzle the vegetables with 2 tablespoons of olive oil and toss to coat evenly.
Pour half of the prepared teriyaki sauce over the chicken and vegetables. Toss everything until evenly coated, then spread them out in a single layer.
Place the baking sheet in the preheated oven and bake for 20 to 22 minutes, or until the chicken reaches an internal temperature of 165°F.
Switch your oven to broil mode and broil for an additional 2 minutes to caramelize the sauce and enhance the flavors.
Remove the baking sheet from the oven and drizzle the remaining teriyaki sauce over the chicken and vegetables for an extra burst of flavor.
Optionally, garnish with sesame seeds or chopped green onions before serving. Enjoy!
Notes
If the sauce thickens too much while cooking, add 1 tablespoon of water at a time until the desired consistency is achieved.