Rinse the quinoa under cold water. Place it in a saucepan with 2 cups of water and a pinch of salt. Bring to a boil, then reduce to a simmer, cover, and cook for 15 minutes until the water is absorbed. Remove from heat and let it sit covered.

While the quinoa cooks, mix the miso paste, honey, soy sauce, and rice vinegar in a small bowl until smooth. Pat the cod fillets dry and season them lightly with salt and pepper. Brush the miso glaze over the top of each fillet.

Heat 1 tablespoon of sesame oil in a large skillet over medium-high heat. Add the bok choy halves cut side down and cook for 2 to 3 minutes until lightly browned. Add the garlic and ginger, then flip the bok choy and cook 2 minutes more until tender. Remove from the skillet and set aside.

In the same skillet, add the remaining tablespoon of sesame oil. Place the cod fillets glaze side up and cook for 3 to 4 minutes. Transfer the skillet to a preheated broiler and broil for 2 to 3 minutes until the glaze bubbles and the fish flakes easily.

Fluff the quinoa with a fork. Divide it among four plates. Top each with a piece of cod, some bok choy, and a sprinkle of sliced green onions and sesame seeds.