Heat 1 tablespoon of oil in a large, heavy-bottomed, oven-safe skillet. When oil is hot remove the chicken pieces from the bag and place skin-side down in the hot skillet. Set the marinade aside. Allow chicken to brown nicely on the skin side, then flip and brown the other side. Remove the chicken from the pan and wipe with a paper towel to remove any burned bits. Add the second tablespoon of oil and the diced onions and cook until the onions are translucent. Add the rice, chicken stock, water, salt, pepper, and the saved marinade to the skillet. Simmer together for one minute then place the chicken breasts on top. Cover and bake at 350 degrees for 35 minutes. Remove the lid, add a few sliced lemons if you like, and bake an additional ten minutes. Taste the rice for doneness. If still too firm, return the skillet to the oven for an additional 5-10 minutes. I needed to add an extra splash of chicken stock at this point. When the rice is cooked to your liking, remove the pot and let rest for ten minutes.