1. Prepare the Teriyaki Sauce

In a medium saucepan, combine soy sauce, water, brown sugar, ground ginger, and minced garlic. Stir well and heat over medium heat.

In a small bowl, mix the cornstarch and water to form a slurry. Once the sauce begins to simmer, gradually whisk in the cornstarch mixture. Continue to cook, stirring constantly, until the sauce thickens. Remove from heat and set aside.

2. Cook the Chicken

Preheat your oven to 375°F (190°C).

Place the chicken breasts on a cutting board and trim off any excess fat. Season lightly with salt and pepper. Heat a skillet over medium heat and lightly coat with olive oil. Cook the chicken for 4–5 minutes per side until golden brown.

Transfer the chicken to a cutting board, allow it to cool slightly, then shred or chop into bite-sized pieces.

3. Stir-Fry the Vegetables

In the same skillet, add the stir-fry vegetables. Cook over medium-high heat for 4–5 minutes, stirring frequently, until tender-crisp. Remove from heat.

4. Assemble the Casserole

Lightly grease a 9×13-inch baking dish. Spread the cooked rice evenly on the bottom of the dish. Layer the shredded chicken over the rice, followed by the stir-fry vegetables.

Pour the teriyaki sauce evenly over the entire casserole, ensuring all the layers are coated.

5. Bake the Casserole

Cover the baking dish with aluminum foil and bake in the preheated oven for 20 minutes. Remove the foil and bake for an additional 10 minutes, allowing the top to slightly brown and the flavors to meld together.

6. Serve

Remove the casserole from the oven and let it cool for 5 minutes before serving. Garnish with sesame seeds or sliced green onions for an extra touch.