Yields: 16 meatballs, 8 servings
Heat oven to 400°F. Place a greased wire rack on an aluminum foil-lined rimmed baking sheet; set aside.
Combine the egg white, Parmesan, bread crumbs, garlic powder, salt and pepper in a large bowl. Crumble chicken over parmesan mixture; mix just until combined. Divide chicken mixture into 16 portions; shape into balls.
Cut feta into 16 cubes, about 1/2-inch each. Press a feta cube into the center of each ball; seal chicken mixture around cheese. Place meatballs on prepared pan. Bake for 20-25 minutes or until a thermometer reads 165°F.
Meanwhile, warm wing sauce and butter in a large saucepan over medium heat until butter is melted, stirring occasionally. Add meatballs; toss to coat. Serve immediately, or transfer to a 3-quart slow cooker. Keep warm on low.