I have struggled to recreate the great Pomme Frites you get in France until I discovered boxed potato starch. (And yes, I've tried the two step process of frying at 325 degrees and 350 degrees.) Here's what worked: (This recipe is for two people.)
1. Cut 2 Russet potatoes into thin, match stick strips. (About 1/4 wide and 1.5 inches long.)
2. Soak the potatoes for 10 minutes in cold water. Drain.
3. Dry potatoes in a salad spinner.
4. Toss potatoes with 1-2 tablespoons of potato starch. (Available at most large markets and Asian groceries.) The potato starch changes the dynamics of frying in peanut oil as it provides a dry starch surface rather than a wet, potato starch surface.
5. Heat peanut oil to 350 degrees and fry using tongs to separate the potato strips.
6. When well browned, remove from the oil and drain on paper towels. (If your frying temperature was correct, there should be virtually no oil on the paper towels.)
7. Toss gently in a bowl with Kosher salt and serve warm.
The potato starch makes this all come together and results in killer Pomme Frites that go great with steak and salad.