OHhhhhhhhhh, that pie sure does look good!
Right now I'm working on a project that calls for making different types of pizzas with dehydrated potatoes either in the dough (actually works quite well) and as a topping (think mashed potatoes applied with a decorating bag and a star tube), topped with bacon bits, ham/Canadian bacon, onion, and a cheddar-mozzarella cheese blend. Also thing about what can be done with shredded potatoes mixed with a little whole egg and flour to make a potato crust (par-bake) and then top either as a breakfast pizza, or as a gluten-free pizza. Potatoes are possibly one of the most overlooked health foods that really seems to work well with pizza.
Have fun, and enjoy those potato pizzas!
Tom Lehmann/The Dough Doctor