Directions

1. Cut potatoes into 1/4-in. julienned strips; soak in cold water for 30 minutes.
2. Drain potatoes; pat dry with paper towels. In an electric skillet or deep-fat fryer, heat oil to 340°. Fry potatoes in batches until lightly browned, 3-4 minutes. Remove with a slotted spoon; drain on paper towels.
3. Increase heat of oil to 375°. Fry potatoes again in batches until crisp and golden brown, 1-2 minutes, turning frequently. Drain on paper towels; sprinkle with 3/4 teaspoon salt.
4. Preheat a cast-iron skillet over high heat, 3-4 minutes. Add olive oil and let heat until rippling. Pat beef dry with paper towels and season all sides with remaining 3/4 teaspoon salt and pepper.
5. Place steak in skillet and cook until a golden brown crust forms, 3-4 minutes. Turn steaks to sides and cook 1 minute, rolling as edges become brown. Turn to uncooked side; add butter, garlic and thyme to pan. Cook another 3-4 minutes, until steaks spring back slightly but are soft when lightly pressed. Use a spoon to baste steaks with butter the last 1-2 minutes of cooking, until desired degree of doneness (for medium-rare, a thermometer should read 135°; medium, 140°; medium-well, 145°). Discard garlic cloves and thyme. Let stand 5 minutes before serving.