In a large pot, sauté onions in oil. Add split peas and bacon bones. Add enough water to cover ingredients, and season with salt and pepper.
Cover, and cook until there are no peas left, just a green liquid, approximately 2 hours. While it is cooking, check to see if water has evaporated. You may need to add more water as the soup continues to cook.
Once the soup is a green liquid remove from heat, and let stand so it will thicken. Remove bacon bones before serving.