Grease a baking pan and place a layer of the thinly sliced onions on the bottom. Then place the chicken, skin side up, single layer, on top of the onions. Set aside.
In a medium size saucepan over medium heat fry up the olive oil and chopped onion and garlic together for about 3-5 minutes, until the onion becomes translucent. Add ketchup, vinegar and maple syrup, stirring well after each addition and then add all the remaing spices. Heat to boiling and pour over the chicken.
Bake, uncovered, for 1 hour, basting every 20 minutes. Check to make sure chicken is done by piercing a thick part with a fork, if the juice runs clear it is likely done. Mine was falling off the bone!
Pre-Heat the oven to 350F / 180C
You can use grade A maple syrup, but the maple flavor can get lost in all the spices. We used grade B for this.