Begin by tearing the bread into small pieces and soaking it in milk for about 5 minutes until completely soft. Drain excess milk and set aside.

In a large mixing bowl, combine ground beef, ground lamb, grated onion, minced garlic, chopped fresh parsley, and the soaked bread. Gently mix until just combined.

Add salt, pepper, and any additional spices to the bowl, mixing thoroughly. Adjust seasoning if needed.

Coat hands with oil, scoop out portions of the mixture, and shape into uniform meatballs about the size of a tablespoon.

Lightly dust each meatball with flour, rolling gently to create a thin coating.

In a large skillet, heat olive oil over medium heat until shimmering. Fry meatballs for about 10-12 minutes, turning occasionally until browned and cooked through.

Transfer Greek Meatballs to a serving platter. Let cool slightly before serving with pita and tzatziki sauce.