In a large mixing bowl, combine ground beef, finely grated onion, uncooked arborio rice, chopped parsley, and dill. Crack in an egg and season with salt, black pepper, and dried oregano. Mix gently until well incorporated.

Form golf ball-sized meatballs and refrigerate for 15-20 minutes to help them hold their shape.

In a wide pot, heat chicken broth and olive oil until it reaches a gentle simmer. Carefully add the chilled meatballs and cover the pot, cooking on low for about 30 minutes.

While the meatballs are simmering, whisk together eggs and lemon juice in a separate bowl. Gradually mix in hot broth to temper the mixture.

Return the tempered mixture to the pot with the meatballs, stirring gently over low heat to thicken the sauce.

Ladle the meatballs into bowls, garnishing with fresh dill or a lemon wedge. Serve warm with crusty bread or rice.