Place eggs in a medium sized pot and cover with cold water by about 1 inch. Bring to a boil, turn off heat and cover with a lid for 6 to 7 minutes. Drain water and rinse eggs under cold water over eggs for about a minute. Let cool, then carefully crack and peel.
In a food processor, combine onion, garlic, butter, and 3 tablespoons parsley. Pulse until minced. Transfer to bowl.
Add ground turkey, egg yolk, bread crumbs, salt and pepper to bowl and mix well.
Transfer meat mixture to a baking dish. Shape into a loaf, making a large gap in the center that is about a ½ inch from the edges on all sides. Place eggs in the middle, then tuck green beans around the eggs lengthwise. Shape meat around eggs, closing the hole and making a loaf. Bake for 50 minutes.
Meanwhile, make the sauce. Combine yogurt, lemon juice, remaining parsley (chopped), mustard, and horseradish. Pour sauce over loaf and serve.
Recipe by Things I Made Today at https://www.thingsimadetoday.com/2013/06/12/non-american-meatloaf/