Preheat oven to 450 degrees.
Using a mandoline or sharp chef’s knife cut potato into paper thin slices. Cut leek into thin rounds and rinse well under cold water. Coat a baking sheet or pizza pan with a thin layer of olive oil or a dusting of cornmeal. On a clean working surface dusted with flour, gently stretch the pizza dough to fit your pan, roughly a 10" x 6" rectangle. Gently place dough in the pan. Layer on potato slices in rows, overlapping and leaving a crust. Place in the oven and bake until crust beings to turn golden.
Meanwhile add leeks to a pan and sautée for about 10 minutes until they begin to caramelize. Remove flatbread from oven. Spread leek over the flatbread and bake in the oven for a couple more minutes, until crust is to your liking. Remove and from oven and sprinkle with minced thyme and salt & pepper.