Rinse the potatoes, and slice them into 1/2-inch thick rounds. It's probably about the width of your pinky.
Adjust the racks in your oven, and slide one into the lowest rack. Preheat oven to 450 degrees F (230 degrees C). Placee a large rimmed baking sheet on the lowest rack as the oven heats up.
Mix a 1/2 teaspoon salt, spice, and onion powder together in a small bowl. Set aside.
Place the potatoes in a medium pot, and fill it with water, until it is about an inch above the potatoes. Add a teaspoon of salt in the pot. Bring the water to boil and reduce the heat to medium-low. Let the potatoes simmer for about 4 to 5 minutes. You want the potatoes to be able to pierce the outer part of the potatoes, but the potatoes should not crumble to pieces.
Drain the water and return the potatoes to the pot. Drizzle 2 tablespoons of oil, place the lid on the pot, and give it a good shake. Add another 2 tablespoons of oil and the spices, place the lid on top of the pot, and shake again. The surface should look a bit powdery.
Take the heated baking sheet from the oven and pour the remaining oil over it. Swirl the oil around so that it covers more surface area of the baking sheet. Line the potatoes on top of the baking sheet in a single layer. Let the potatoes bake for 10 minutes and rotate the entire baking sheet. Check to see if the bottoms are browned yet. Bake for about another 10 minutes. Take the potatoes out and flip them over with tongs or a spatula. Bake the potatoes for another 10 to 15 minutes, until the bottoms are golden brown.
Let the potatoes cool for a few minutes before serving.