Steak Frites

Ingredients

• 800 g (1¾ lb) flat iron steak, in 2 pieces about 3 cm (1¼ in) thick
• 1 tsp salt, plus more for the fries
• ½ tsp black pepper
• 1 tbsp vegetable oil
• 30 g (2 tbsp) butter
• 2 cloves garlic, smashed
• 3 sprigs fresh thyme
• 1 kg (2¼ lb) floury potatoes, such as Russet
• About 1 litre (4 cups) oil for the fries
• Dijon mustard or béarnaise, to serve

Steps

1. Take the steaks out of the fridge 30 minutes ahead. Pat dry and season all over with the salt and pepper.
2. Cut the potatoes into 1 cm (⅜ in) sticks, soak in cold water for 15 minutes, then drain and dry very well in a towel.
3. Heat the frying oil to 150°C (300°F) in a deep, heavy pot. Fry the potatoes in 3 batches for 5 minutes each, until soft and pale. Lift out and drain on a rack.
4. Heat a heavy skillet over high heat until just smoking. Add the vegetable oil and lay in the steaks away from you.
5. Pan-fry for 3 minutes without moving, until a deep brown crust forms. Flip and cook 2 minutes more.
6. Lower the heat to medium, add the butter, garlic and thyme, and baste the steaks with the foaming butter for 1 minute. Aim for 52°C (125°F) inside for medium-rare.
7. Move the steaks to a board and rest for 8 minutes. Meanwhile, raise the frying oil to 190°C (375°F) and fry the potatoes again for 2 to 3 minutes, until golden and crisp.
8. Toss the fries with salt. Slice the steak against the grain, pour over the pan juices and serve with mustard.

Notes

• Shortcut: use good frozen fries baked or air-fried to the packet directions and skip the double fry.
• Other cuts: hanger, sirloin or ribeye all work; adjust the time to thickness.
• Doneness: flat iron is best at medium-rare to medium; past that it turns firm.
• Make ahead: do the first fry earlier in the day, drain and leave at room temperature up to 2 hours, then finish with the second fry.
• Pair with: a sharp green salad in a Dijon vinaigrette, the bistro way to cut the richness.