Place the potato matchsticks in a bowl of water and let stand for 15 minutes.
Heat enough peanut oil to come 4 inches up the sides of a large deep saucepan to 350 degrees F. Preheat a grill.
Drain the potatoes, rinse under cold water and drain again. Pat dry with towels. Deep-fry the potatoes in batches until golden brown, 3 to 5 minutes. Remove with a slotted spoon and drain on paper towels. Sprinkle with salt immediately.
Sprinkle both sides of the steaks with salt and pepper. Grill about 3 minutes per side for medium rare. Transfer the steaks to a serving plate.
Add the shallots and minced garlic to a skillet and cook until softened, about 2 minutes. Pour in the sherry to deglaze, scraping up any bits on the bottom and cook until almost dry. Add the heavy cream, white wine and peppercorns and simmer, whisking, until lightly thickened.
Drizzle the sauce over the steaks, add the frites to the plate and serve immediately.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.