Start by whisking the soy sauce, honey, grated ginger, minced garlic, sesame oil, and rice vinegar together in a small bowl. The mixture should look glossy and smell fragrant. Let it sit for about 5 minutes while you preheat your oven to 400°F, allowing the flavors to blend together.
Line a baking sheet with parchment paper for easy cleanup. Pat the cod fillets dry with paper towels – this step helps the glaze stick better. Place the fillets on the prepared sheet and brush them generously with the ginger soy glaze, making sure they are well-coated.
Slide the baking sheet into the preheated oven and bake for 12–15 minutes. The cod is ready when it flakes easily with a fork and the glaze looks sticky and slightly caramelized. For extra crispiness, switch the oven to broil for the last 2 minutes.
Once baked, remove the cod from the oven and let it rest for 1–2 minutes. Sprinkle chopped scallions and sesame seeds over the top for freshness and crunch. For more flavor, drizzle a spoonful of leftover glaze on the fillets before serving.