Slice potatoes into 1/4" slices. Cut onion into slices.
In a greased 9 x 13 baking dish, layer potatoes and onions alternately and set aside.
In a large saucepan, melt butter over medium heat. Once melted, add 1/2 cup flour to the saucepan and stir to create a roux.
Turn heat to med-high and slowly add in milk, 1 cup at a time, stirring well to get rid of any lumps. Add salt and pepper to taste.
Pour white sauce over potato and onions and bake at 350°F for 15 minutes, uncovered.
In a shallow dish, beat egg with 1 tablespoon water. In a separate dish, combine 1 cup flour, 1 cup bread crumbs, and garlic powder.
Dredge the pork chops in the egg mixture, then the flour mixture.
Add vegetable oil to skillet and heat to medium-high. Cook pork chops, for 4-6 minutes a side, until lightly browned. They do not need to be cooked all the way through.
Arrange pork chops on top potatoes and onions. Return dish to oven and bake for 45 minutes, or until pork chops reach an internal temperature of 145°F.