Preheat the oven to 375°F.
In a large bowl, mix together the ground beef, bread crumbs, egg, grated onion and Ranch dressing mix until well blended.
Shape into 1-inch meat- balls and place on a 10 x 15-inch jellyroll pan or any baking sheet with sides to catch the grease.
Bake for 30 minutes in the pre- heated oven, turning them over halfway through.
While the meat- balls are roasting, mix together the ketchup, cider vinegar, cola, chopped onion and green pepper in a slow cooker.
Season with seasoning salt, pepper and Worcestershire sauce.
Remove meat- balls from the baking sheet and place into the sauce in the slow cooker.
Cover and cook on low heat for 3 hours, then remove the lid and cook for an additional 15 minutes before serving.
Serve, and enjoy!