Add the onions to a large pan with the olive oil and season with salt and pepper. Cook over medium heat, stirring occasionally, for about an hour, until drastically reduced in size and nicely browned. You will need to adjust the heat down throughout cooking to get a nice brown without burning.
Preheat oven to 325
In a heavy bottom oven safe pot, sear the chicken thighs for a few minutes per side to brown. Stir in the garlic and cook another 1 minute.
Pour in enough stock to just come to the top of the chicken and stir in the thyme. Top with the onions and gently stir to combine, but keep the onions mostly on top.
Bake uncovered for about an hour until the chicken is just about falling apart.
Serve with parsley.
Serving suggestions - Cauliflower rice, baked potatoes, or Warrior Bread to soak up the broth.