Salt chicken thighs for one hour, leaving out at room temperature if you have time.
Heat oil in large frying pan. Brown chicken on medium high until the skin is browned. I do this because the skin doesn't get as crispy in the oven. This will aid in that.
Clean out pan if this is the pan you are using to roast. A big cast iron braiser, roasting pan, or sheet pan will also work.
Slice onions, medium thickness about 1/4 inch.
Seed and slice peppers into strips.
Peel garlic cloves.
Layer the onions, peppers, chicken. The juice from the chicken will fall into the vegetables.
Add garlic cloves whole.
If adding sausage, add in raw sausage links.
Bake at 375 degrees F. for 45 -60 minutes until the sausage and onions are caramelized.