Preheat oven to 300.
Line a baking sheet with foil and grease it with cooking spray; set aside.
Combine flour, butter, cheese, parsley, garlic powder, salt and pepper in your mixer's bowl.
Set mixer to low and beat just until combined.
With floured hands, work the dough with your hands until it holds together.
Pinch off small pieces of dough and make into lime-sized balls.
Take the dough ball in between your hands and roll into sticks.
Place the mozzarella sticks on previously prepared baking sheet.
In a small bowl, whisk together egg yolk and milk.
Brush the tops of each mozzarella stick with egg mixture.
Bake for 14 to 16 minutes, or until just starting to brown.
Remove from oven and cool completely.
Serve with warm marinara sauce.