1. Preheat oven to 400F (200C).
2. Slice mushrooms and finely chop garlic.
3. Mix together beef broth, vinegar and garlic.
4. Transfer mushrooms to a baking dish. Pour the broth mixture over the mushrooms, season with salt and pepper, then stir. Top mushrooms with about 10 small thyme sprigs.
5. Season chicken legs with salt, garlic powder and pepper on all sides. Place on top of the mushrooms. Add a few more sprigs of thyme.
6. Bake chicken and mushrooms in the preheated oven for 50-60 minutes, until a nice crust is formed.
7. Transfer chicken to a plate, remove thyme sprigs, stripping off the leaves (or needles) of some of them, to add extra flavor to the sauce.
8. To the mushrooms, add coconut cream, coconut milk and starch, stir well. Wait a couple of minutes for the sauce to thicken.
9. Top chicken with mushroom sauce and serve.