Combine ground beef, chopped onion, minced garlic, egg, bread crumbs, parsley, oregano, salt, and pepper in a large bowl. Mix well until all ingredients are thoroughly combined and form small, uniform meatballs.

Heat vegetable oil in a large skillet over medium-high heat, then carefully add the meatballs in a single layer. Brown the meatballs on all sides, ensuring they are cooked through; remove and set aside.

In the same skillet, whisk together chicken broth, lemon juice, and cornstarch. Bring the mixture to a gentle simmer, stirring constantly, until it begins to thicken.

In a separate small bowl, whisk the egg yolks, then gradually temper them by slowly adding a small amount of the hot broth mixture while continuously whisking.

Pour the tempered egg yolk mixture back into the simmering sauce in the skillet and continue to cook, stirring constantly, until the sauce thickens to your desired consistency.

Return the browned meatballs to the skillet with the lemon sauce and simmer for 5-7 minutes, ensuring the meatballs are heated through and coated in the sauce.

Stir in fresh dill before serving for an added burst of flavor and freshness. Serve immediately over cooked rice or pasta.