What You Need
Add beef, pork, milk, egg, mint, oregano, 1 ¼ teaspoon kosher salt, and ½ teaspoon black pepper to a large bowl. Using your hands, crumble the bread into small bits into the bowl with the beef mixture. Grate the red onion on the large holes of the box grater and finely grate the garlic into the bowl with the beef mixture. Using clean hands, mix until incorporated, but do not overmix.
Roll the beef mixture into 1 1/4" balls (about the size of golf balls) and arrange on a small baking sheet or plate. Cover and refrigerate until well chilled at least 30 minutes or up to 1 day.Heat the HexClad Hybrid Double Burner Griddle over medium, brush to coat the entire griddle. Evenly space the meatballs on the griddle and cook, turning frequently, until brown all over, about 10 minutes. Remove meatballs to a plate and sprinkle with sea salt.