In a large bowl, combine 1 pound of ground beef, grated onion, minced garlic, chopped fresh parsley, beaten egg, breadcrumbs, dried oregano, salt, and pepper. Use your hands or a spatula to mix gently, ensuring all ingredients are evenly incorporated without overmixing. This step should take about 5 minutes.

With the mixture ready, scoop out portions and roll them into walnut-sized meatballs, approximately 1 to 1 ½ inches in diameter. Place the shaped meatballs on a clean plate, leaving space between them to prevent sticking. Aim for about 20 meatballs to ensure ample servings. This step will take around 10 minutes.

Heat a large skillet over medium heat and add a generous drizzle of olive oil, enough to cover the bottom. Once the oil is shimmering, gently place the meatballs in the skillet in a single layer, being cautious not to overcrowd them. Brown the meatballs for about 3-4 minutes on each side until golden brown but not fully cooked, then carefully transfer them back to the plate.

In a mixing bowl, whisk together 1 ½ cups of chicken broth, the juice and zest of 2 lemons, and 1 tablespoon of cornstarch until smooth and well combined. This will create your luscious lemon sauce. Ensure there are no lumps from the cornstarch.

Pour the fragrant lemon sauce over the browned meatballs that are still in the skillet. Stir gently to combine, allowing the meatballs to bask in that delicious lemon goodness.

Reduce the heat to low, cover the skillet with a lid, and let the meatballs simmer in the lemon sauce for about 15 minutes. Stir occasionally, ensuring that the meatballs remain moist and the sauce does not stick to the bottom.

Once the Greek Meatballs in Lemon Sauce are fully cooked and thickened, carefully transfer them to a serving platter. Garnish with additional chopped parsley or crumbled feta cheese. Serve hot over orzo, rice, or creamy mashed potatoes.