Trim fat from meat. cut meat crosswise into four slices. Place each slice between two pieces or plastic wrap. Using the flat side of a meat mallet, pound meat lightly until about ¼-inch thick. Remove plastic wrap.
In a shallow dish stir together flour, garlic salt, and pepper. In another shallow dish combine egg and milk. Place bread crumbs in a third shallow dish. Dip meat into flour mixture to coat. Dip into egg mixture, then into bread crumbs, turning to coat.
In a large cast-iron or other heavy skillet heat oil over medium heat. Add meat; cook for 6 to 8 minutes or until meat is slightly pink in center, turning once.
Serve meat in buns with toppings of choice.
Recipe by Not Just Sunday Dinner at https://notjustsundaydinner.com/pork-tenderloin-sandwiches/