In a large ziplock bag, combine ¾ cup all-purpose flour, ½ teaspoons mustard powder, 1 teaspoon garlic powder, 1/4 teaspoon cracked pepper, and 1/2 teaspoon seasoned salt.
Add 4 1/2 inch thick boneless pork loin chops, one at a time, and shake to coat.
In a large skillet, brown chops in 2 tablespoons vegetable oil on each side.
Transfer the chops to a greased 5 quart slow cooker, add 1 large sliced onion.
Place leftover flour from the ziplock in a small bowl; whisk in 2 cups chicken stock until smooth. Pour over chops.
Cover and cook on low for 2 to 3 hours or until meat is tender. (In my crockpot - 2 hours was plenty).
Remove pork to a serving plate and keep warm. Whisk pan juices until smooth; serve with pork.