The meal prep MVP. Teriyaki chicken over rice is simple, high protein, and reheats perfectly — which is why it shows up in gym bags everywhere.
In a small saucepan, combine the soy sauce, mirin, brown sugar, rice vinegar, minced garlic, and grated ginger. Bring to a gentle simmer over medium-low heat, stirring continuously until sugar is dissolved.
Mix cornstarch and water in a small bowl to make a slurry, then add to the saucepan. Stir and simmer for 2-3 minutes until the sauce thickens to a glossy consistency, then remove from heat.
Heat a large nonstick skillet over medium-high heat. Add the chicken thighs and cook without moving for 3-4 minutes to develop a good sear, then flip and cook the other side for another 3 minutes.
Pour half of the teriyaki sauce over the chicken. Reduce heat to medium-low and cook, turning occasionally, for 4-6 minutes, basting with sauce until chicken is glazed and cooked through. Remove and let rest 2 minutes before slicing.
Steam the broccoli florets until crisp-tender, about 3 minutes, then immediately transfer to a plate to stop further cooking.
To assemble the bowls, divide cooked rice among four bowls. Top with sliced chicken, arrange broccoli on the side, drizzle extra sauce, and garnish with sliced scallions.