In a large mixing bowl, combine the ground beef (or lamb), breadcrumbs, grated Parmesan cheese, chopped parsley, dried oregano, garlic powder, onion powder, and a generous pinch of salt and pepper. Using your hands or a spatula, mix these ingredients together until well combined.
Pour the beaten egg into the mixture, and continue to mix until everything is evenly incorporated, forming a cohesive mixture.
With your hands, shape the mixture into small meatballs, about 1 inch in diameter, ensuring they are uniform in size for even cooking.
In a large skillet, heat the olive oil over medium heat. Once hot, gently add the meatballs in batches, ensuring not to overcrowd the pan. Cook for approximately 5-7 minutes, turning occasionally to brown all sides evenly. Once browned, remove the meatballs from the skillet and place them on a plate to rest.
Using the same skillet, add the chicken broth, freshly squeezed lemon juice, and lemon zest. Stir to combine and bring the mixture to a gentle simmer, allowing the flavors to meld.
If you prefer a thicker sauce, mix the cornstarch with a small amount of cold water to create a slurry, then slowly stir it into the simmering sauce. Cook for an additional few minutes until the sauce has thickened to your desired consistency.
Carefully return the meatballs to the skillet, ensuring they are submerged in the lemon sauce. Cover the skillet and let the meatballs simmer in the sauce for about 10-15 minutes, enabling them to absorb the bright lemon flavors.
Before serving, taste the sauce and adjust the seasoning with salt and pepper if needed.
Notes
Serve with rice or crusty bread to soak up the sauce.