In a large mixing bowl, combine ground beef, grated onion, arborio rice, chopped parsley, dill, egg, oregano, salt, and pepper. Mix gently until just combined and allow to rest.

Form the mixture into golf ball-sized meatballs and refrigerate for about 15-20 minutes.

In a large pot, heat chicken broth and olive oil over medium-low heat until gently simmering.

Carefully add meatballs to the pot, cover, and cook on low heat for about 30 minutes, stirring occasionally.

In a separate bowl, whisk eggs and lemon juice, then temper with hot broth to prevent curdling.

Return the tempered mixture to the pot, stirring gently until the sauce thickens slightly.

Serve warm, garnished with dill or lemon wedges alongside rice, bread, or salad.