Preheat your oven to 425 degrees. Line a baking sheet with foil and set aside.

Wash and pat dry your potatoes. Cut 1/2 inch wide slits into the tops of your potatoes - about 3/4 of the way down. Be careful to not cut them all the way through. If you do, that's okay. They just wont be as pretty. Arrange the potatoes on your baking sheet.

Whisk together the oil, salt, chili powder, garlic powder and cayenne. Using a pastry brush, brush the oil spice mixture over each potato, ensuring the oil drips down into the slits.

Place in the oven and bake until fork tender, reapplying the oil every 20 minutes. Medium potatoes should be done in approximately 1 hour.