Line a baking pan with aluminum foil and add oil. Turn oven to 400 degrees, and add pan immediately so everything heats up at the same time
Fill a medium saucepan with cold water. Add a little salt, and potatoes. Bring to a boil, and par-boil for 7-10 minutes. Potatoes are ready when you can pierce the flesh easily with a fork
Drain potatoes, and allow to cool for about 3 minutes, or until they are cool enough to hold
Using a fork, score the flesh of the potatoes
When the oven is ready, add the potatoes, flesh-side down. Potatoes should sizzle immediately.
After 10 minutes, turn potatoes to one side. Allow to cook for another 10 minutes, then turn potatoes again and cook for 10 minutes
If needed, turn potatoes back to flesh side and allow to cook for a few more minutes
Remove potatoes and drain on a paper towel. Immediately season with coarse sea salt
Finish by seasoning with parmesan cheese and thyme.
Serve with dipping sauce combination of spicy brown and yellow mustard