Mix marinade ingredients together in a bowl and marinate the quail for 40 minutes, turning every 10 minutes.
Preheat oven to 350 °F (180°C).
In a large oven-safe skillet, sauté onion in 4 tbsp oil on the stovetop. Add the quail and brown on all sides. Pour over the marinade and bake quail uncovered in oven for 45 minutes.