In a mixing bowl, combine the white miso paste, rice vinegar, honey, garlic paste, soy sauce, and ginger paste. Whisk until smooth and well-blended.
Place the chicken thighs in a baking dish. Pour the marinade over the chicken, ensuring each piece is generously coated. Cover with plastic wrap and refrigerate for at least 1 hour, or ideally overnight for maximum flavor.
Preheat your oven to 400°F (200°C). This high temperature will help crisp the skin while keeping the meat juicy.
Remove the chicken from the marinade, allowing excess marinade to drip off. Place the chicken thighs skin-side up in the baking dish. Bake for 35-45 minutes, or until the skin is golden brown and a meat thermometer reads 165°F (75°C).
Once cooked, remove the chicken from the oven and let it rest for about 5 minutes. This helps retain the juices.
Serve your miso chicken with steamed rice or a fresh salad, drizzling any remaining juices over the top for added flavor.