Pre-heat oven to 450 degrees. Line a large rimmed baking sheet with aluminum foil. Mix the buttermilk and crushed croutons together and let sit for 2 minutes. In a large bowl, combine the beef, pork,eggs, salt, pepper, Worcestershire, onion powder, garlic powder, and crouton mixture (don't over mix). Scoop into walnut-size meatballs and place close together on the baking sheet. Slightly flatten with your palms. BAke for 10-12 minutes, until cooked through.