In a medium bowl, combine the minced garlic, lemon zest, chopped parsley, panko breadcrumbs, grated onions, crumbled feta, egg, dried oregano, salt, and pepper. Mix together using a fork until well blended. Add the ground chicken and gently mix until just combined to avoid overworking the meat. Form the mixture into 24-28 meatballs using a cookie scoop or about 1 ½ tablespoons of mixture each.

Heat a large skillet over medium-high heat and drizzle in a little oil. Add the meatballs in batches to avoid overcrowding. Cook for 5-7 minutes, turning occasionally to brown all sides evenly, until fully cooked through. Remove the meatballs and set aside on a plate.

To the same skillet, add 2 tablespoons of butter and the minced garlic. Cook for 30 seconds, stirring to prevent burning. Sprinkle in the flour and whisk continuously for another 30 seconds to cook out the raw flour taste.

Slowly pour in the chicken stock while whisking continuously to create a smooth sauce. Bring the mixture to a simmer and cook for about 3 minutes until the sauce slightly thickens. Reduce the heat to the lowest setting and keep warm.

In a small bowl, whisk together the lemon juice and egg yolks until smooth. Gradually add three tablespoons of the warm sauce to the egg mixture, whisking constantly to temper the yolks and prevent curdling.

Slowly pour the tempered egg yolk mixture back into the skillet with the sauce on the lowest heat. Increase the heat to medium and stir continuously for 4-6 minutes until the sauce thickens to your desired consistency. Stir in the nutmeg and lemon zest. Taste and adjust seasoning with salt and pepper as needed.

Stir in the remaining tablespoon of butter, allowing it to melt slowly into the sauce. Add the green olives and return the cooked meatballs to the skillet. Warm everything together for 1-2 minutes so the flavors meld.

Serve the meatballs and creamy lemon sauce over buttered orzo, rice, or quinoa. Optionally, pair with fried bread to soak up the luscious sauce.