Preheat oven to 450~. Place ribs in a baking pan. Put lemon and onion slices on top of meat. Bake for 20 minutes at 450~. Combine all other ingredients in a pot and bring to a boil. After ribs have browned for 20 minutes, pour sauce over meat and bake for 1 hour and 15 minutes at 350~. Baste every 15 minutes.