Preheat oven to 450'F. Put a large metal baking tray into the oven and let it heat up while the oven heats up. This ensures the crispness of the potatoes. Put the rack on the bottom section of your stove.
Slice your potatoes 1/2" thick. Put 1" of water in a large metal pot and add some seas salt, then put the potatoes in the water and boil then simmer until the potatoes are slightly done, about 5 minutes.
Test the potatoes for doneness. They should still be somewhat hard inside. Drain well once they are done.
In a large bowl, add 2 tablespoons of oil with the sea salt. Add the hot potato slices and toss. Add two more tablespoons of oil and toss again. The tossing is important. You want to rough up the outside of the potatoes a little to ensure they get crisp.
Once the oven is heat to the desired temperature, remove the baking pan and put a tablespoon of oil on it and roll it around to ensure the whole pan is oily. This keeps the potatoes from sticking and ensures crispiness.
Place the potatoes in a single layer on the hot baking tray and put in the oven for 15-25 minutes.
Once that is done remove the potatoes and flip them over to the other side and bake for another 10-20 minutes.
These are best served immediately as they will dry out.