Cut apart spare ribs if not already done so. Place in baking pan and bake in a 350 oven for 35-40 minutes. Drain off any rendered fat.
Saute the onion in the oil. Add lemon juice, vinegar, Worcestershire sauce, brown sugar, water, chili sauce, salt and pepper. Cook slowly for 20 minutes to reduce and thicken.
Pour over spare ribs, and bake for an additional hour.