This was given to me by a co worker over 30 years ago; She had won several blue ribbons with it. She is gone now but I think of her every time I make this. I consider this my go to "company" dessert that can be made ahead. Now whenever I invite people over, they ask for this.
Preheat oven to 350 degrees. Grease sides and bottom of a 10-inch deep dish pie pan. Set aside. (I have used a 9x9-inch glass baking dish and adjusted baking time)
In a large bowl add flour, salt, baking powder and dry vanilla pudding; mix until well combined. Add melted butter, egg and milk; beat for 2 minutes with mixer. Pour into pie pan and smooth out evenly. Arrange peaches slices on top.
In a small bowl beat cream cheese until fluffy; add 1/2 cup sugar and 3 tbsp of reserved peach syrup. Beat 2 minutes. Spoon over peaches to within one inch of pan edge.
OPTIONAL: Mix together 1 tbsp sugar and 1 tsp cinnamon and sprinkle on top before baking.
Bake 30-35 minutes or until golden brown. Chill 4 hours or overnight before serving.