First, go ahead and fill a large bowl with cold water (preferably ice water) and a generous sprinkle of salt. Set aside somewhere safe (like in your kitchen sink).
Slice the potato into thin strips about 1/4" thick. The thinner, the crispier your french fries will be. Then slice long, shoestring-style potatoes from each strip. Make sure to separate the shoestrings so they aren't sticking together.
Place the shoestrings in the cold, salted water and soak them for about 15-20 minutes. This will help remove the starch from the potatoes so they get crispy when you fry them.
Meanwhile, go ahead and prepare the Rosemary Garlic Oil: Pour the olive oil into a small pan and heat it over Medium-Low heat. Add the rosemary, garlic chunks, and thyme (be careful, the oil may splatter a bit). Cook the herbs in the oil for about 30 seconds, and then remove from the heat. Allow the oil to cool as you continue with the fries.
Strain the water out of the potatoes. Lay the potatoes in a single layer on top of paper towels and pat them dry. Allow to air dry for about 10 minutes to make sure as much moisture is removed as possible.
Meanwhile, line a separate large plate or cookie sheet with paper towels. Set aside for later.
As the potatoes dry, pour the peanut oil into a large pot or dutch oven and heat to 350 F.***
Working in small batches, fry the potatoes for about 2-3 minutes, or until lightly golden. Place the cooked potatoes back on the paper towels to drain while you work on the next batch.
Once all of the potatoes have been fried, make sure the oil is heated to 350 F again. Working in small batches again, fry the potatoes a second time for another 2-3 minutes, until they turn a deep golden brown. Remove the potatoes from the oil and place them on the prepared plate or cookie sheet to drain.
Once all of the potatoes have been fried, drizzle them in the rosemary garlic oil (you may not need all of it), and then sprinkle on the flakey sea salt, parmesan, and parsley.
Like all french fries, these are best enjoyed immediately! Check out the blog posts for tips on how to reheat them.