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 pieces of dough and shape the dough into lime-sized balls.
Take the dough ball in between your hands and roll into sticks.
Place the mozzarella sticks on the baking sheet.
In a small bowl, whisk together egg yolk and milk.
Brush the tops of each mozzarella stick with the 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.
Notes
Flouring Hands: Flour your hands when working with the dough to prevent it from sticking. This will make the dough easier to handle and shape.
Uniform Sticks: Try to keep the size of your mozzarella sticks uniform. This helps to ensure that they bake evenly and at the same time.
Brushing with Egg Mixture: The egg and milk mixture gives the sticks a nice golden brown color. Be sure to cover the entire surface for the best results.
Checking Doneness: Keep an eye on the mozzarella sticks towards the end of the baking time. You want them to be just starting to brown, not overcooked.
Cooling Down: Let the sticks cool completely before serving. This allows them to firm up and makes them easier to handle.
Serving Sauce: Marinara sauce pairs well with these mozzarella sticks, but you can also try other sauces like ranch or aioli for a different flavor profile.