The best, most crispy frites are always cooked in two stages at 2 different temperatures; plan to have the first stage of cooking completed and then do the final crisp cooking of the frites as the steaks rest.
Wash and peel the potatoes; cut them into frites; the size of the frites is your choice but shoestring size, about ¼-inch square, always maximizes the crispy flavor that complements the steak.
Hold the frites in room temperature or lukewarm water until ready to fry.
Lay them out on layers of paper towels and pat dry with additional paper towels before frying.
Add the canola oil to the deep fryer and bring to 350°F.
Fry the potato sticks until just beginning to crisp but not brown; about 6 to 8 minutes for shoestring fries.
Remove from oil and drain on paper towels; these frites will likely go limp as they cool; this is perfectly normal; they will re-crisp in the second fry.
Turn off the deep fryer until ready to fry again.
In the last few minutes of cooking time on your steaks, bring the temperature of the oil to 375°F in the deep fryer; this allows the oil to heat when ready for the final fry of the frites as the grilled steaks rest.
Fry for an additional 6 to 8 minutes or until the frites begin to turn a light golden brown and become quite crispy.
Remove from oil; drain on paper towels; toss with a pinch of kosher salt to season before serving with the steak and gravy.