Step 1: Marinate the Cod

1. In a small bowl, whisk together soy sauce, honey, rice vinegar, ginger, garlic, sesame oil, red pepper flakes, and black pepper.
2. Place the cod fillets in a shallow dish or zip-top bag and pour the marinade over them.
3. Cover and refrigerate for at least 20 minutes, allowing the fish to absorb the flavors.

Step 2: Prepare the Casserole Base

1. Preheat the oven to 375°F (190°C).
2. Lightly grease a 9×13-inch baking dish.
3. Spread the cooked brown rice or quinoa evenly across the bottom of the dish.
4. Layer the bok choy, bell pepper, carrot, snap peas, and half of the green onions on top of the rice.

Step 3: Make the Sauce

1. In a small saucepan over medium heat, whisk together broth, cornstarch, soy sauce, honey, and ginger.
2. Bring to a gentle simmer, stirring continuously until the sauce thickens slightly (about 2-3 minutes).
3. Remove from heat and set aside.

Step 4: Assemble the Casserole

1. Remove the cod fillets from the marinade and arrange them on top of the layered vegetables.
2. Pour the prepared sauce evenly over the fish and vegetables.
3. Sprinkle with remaining green onions and sesame seeds.

Step 5: Bake the Casserole

1. Cover the dish with foil and bake for 20 minutes.
2. Remove the foil and bake for another 10 minutes, allowing the cod to develop a light glaze.
3. Once the fish is tender and flakes easily with a fork, remove from the oven.

Step 6: Serve and Enjoy

1. Let the casserole rest for 5 minutes before serving.
2. Garnish with additional sesame seeds or a drizzle of sesame oil for extra flavor.
3. Serve warm with a side of steamed greens or miso soup for a complete meal.