For the Chicken:
In a large pot, place the chicken and pour over the water and season with salt and pepper. Cook on medium low heat, until the chicken is cooked through. Let cool, and then shred finely. Set aside.
For the White Sauce:
In a medium sauce pan, melt the butter and add the onions. Fry the onions on a medium high heat until they are just translucent, don't let them turn golden.
Add the flour and stir for 1-2 minutes, until the flour is cooked through.
Slowly pour in the milk, while continuously stirring. Keep stirring until the sauce thickens up. If you don't continuously stir, lumps might form in the sauce. The sauce is ready when it is thick and coats the back of a spoon. The sauce must be thick so that it coats the chicken properly.
Season with salt, pepper, garlic powder and add the finely chopped parsley.
Now stir in the shredded chicken, and make sure it is fully combined with the sauce.
To Assemble the Cheesy Alfredo Chicken Bread:
Preheat oven to 390 F (200 C) and line a baking sheet with parchment paper or foil. If using foil, lightly grease it with oil.
Slice the french bread loaves lengthwise.
Spread the chicken mixture on each french bread and then top with shredded mozzarella cheese.
Bake for about 10 minutes or until the cheese has melted.