Before You Begin
Prepare your slow cooker and ingredients as needed. Cooking times and results may vary depending on your equipment and ingredients.
In a large bowl, gently mix ground beef, ground pork, breadcrumbs, egg, salt, pepper, garlic powder, onion powder, and minced onion until just combined. Avoid overmixing.
Shape the mixture into evenly sized meatballs, about 1½ inches each.
Lightly grease the slow cooker insert.
In a separate bowl, whisk together ranch seasoning, pepperoncini, melted butter, Worcestershire sauce, and cream of mushroom soup until smooth.
Place the meatballs in the slow cooker and pour the sauce evenly over the top.
Cover and cook on LOW for 4–6 hours or HIGH for 2–3 hours, until the meatballs are tender, cooked through, and reach an internal temperature of 165°F (74°C).
Meatballs are done when they are firm, no longer pink inside, and reach an internal temperature of 165°F (74°C).
Let rest for 10 minutes before serving.