Wash and then slice the potatoes extra thin. (This is the most time-consuming part.) 

In a bowl generously coat in olive oil -- don't be skimpy -- then salt and pepper. 

Spread the potatoes on a baking tray and cook at 425 for 15 minutes. Toss potatoes and cook for another 15 minutes. Check to make sure they are nice and crispy -- they should be slightly brown. (Tip, I tossed mine again and put them in for an extra five minutes watching them carefully.)