Preheat the oven to 400°F (200°C). Spray a 9x13x2 inch baking dish with cooking spray.
Pat the chicken thighs dry with paper towels and set them aside.
In a large bowl, whisk together 1/4 cup white miso paste, 2 tablespoons rice vinegar, 2 tablespoons honey, 1 tablespoon garlic paste, 1 tablespoon soy sauce, and 1 teaspoon ginger paste until smooth.
Add the chicken thighs to the bowl and rub the miso mixture over each piece to coat evenly. Let the chicken marinate in the mixture for 10 minutes.
Place the chicken thighs skin-side up in the prepared baking dish, arranging them in a single layer. Brush any remaining marinade over the tops.
Bake uncovered for 35–40 minutes, or until the chicken reaches an internal temperature of 165°F (74°C) and the skin is browned and slightly crisp.
Remove from the oven and let the chicken rest for a few minutes before serving.