You'll notice in my photos I have chunky diced potatoes on the top of my pie, this is another option. I sliced all of the potatoes, setting 2 aside. Just before putting the pie in the oven, I peeled and diced the remaining potatoes and scattered them on the top of the pie.
It gives the pie a great look but just be sure you cook the pie fully so the potatoes are cooked all the way through.