Soak bread crumbs or panko in milk for at least an hour, until very soft
Cook onions in oil on low/medium heat until translucent and season with salt and pepper
Place ground beef in a mixing bowl. Add milk and bread crumb mixture, which should be a soft, cohesive mass. Add eggs, whole or whisked. Then add all other ingredients. Mix well with a hook attachments in a stand mixture for 10-15 minutes. Refrigerate meatball mixture for about an hour.
Preheat oven to 450°F. Scoop or hand roll portions into size you want for meatballs. Place meatballs on a baking sheet or large flat sauté pan and bake for 5 minutes on each side, rotating occasionally to get color on each side.
