In a large mixing bowl, combine ground beef, grated onion, arborio rice, chopped parsley, dill, one egg, oregano, salt, and pepper. Mix gently until well-combined and chill in the refrigerator for 15 minutes.

Scoop and shape the mixture into golf ball-sized meatballs and place them on a parchment-lined baking sheet.

In a wide pot, heat chicken broth and olive oil over medium heat until simmering. Add meatballs carefully and simmer on low heat for 30 minutes.

While the meatballs are cooking, whisk together eggs and lemon juice. Temper the egg mixture by adding hot broth while whisking constantly.

Once tempered, slowly pour the egg mixture back into the pot and stir gently to thicken the sauce.

Remove from heat and adjust seasoning. Serve warm with crusty bread or rice.