1. Spread one side of each slice of bread with mayonnaise. Top each with slice of cheese. Make 4 sandwiches, sandwiching the turkey between 2 slices of the bread, cheese side on inside of sandwich.
2. Beat together eggs and milk in shallow bowl or pie plate.
3. Heat oil in large skillet. Dip sandwiches on both sides into egg mixture. Fry sandwiches in skillet, turning once until browned on both sides. Dip sandwich into gravy as you eat.