Methods

1. Place a wire rack on each of two baking sheets.
2. To make the frites, place the potatoes in a large bowl filled with enough cold water to cover them completely. Let sit covered in the refrigerator for at least 30 minutes, or up to 16 hours. Drain the potatoes and lay them out on clean, dry, lint-free kitchen towels and pat dry. Transfer the potatoes to a large mixing bowl, sprinkle with the cornstarch, and toss to coat well. The cornstarch coating is essential for a crisp exterior, so coat thoroughly and on all sides to do this properly. Transfer and divide between the wire racks, spacing the potatoes so they don’t stick to each other. Let sit for 30 minutes. The cornstarch will dry and form a thin white coat on the potatoes.
3. Meanwhile, to make the smoky anchovy butter, chop the anchovies and sprinkle them with a pinch of salt and black pepper. Using the blunt side of the knife, smash and smear the anchovies to form a smooth paste. Transfer the paste to a small mixing bowl. Add the butter, Calabrian chillies, garlic, chives, and liquid smoke and combine with a fork. Keep aside.
4. While the potatoes dry, in a Dutch oven over medium heat, heat the neutral oil to 300°F [150°C]. When the fries are dry and the oil is at temperature, add the potatoes in batches and cook for 4 minutes. You may need to play with the heat a bit while frying to keep the oil as close to the temperature as possible. Remove the fries with a slotted spoon or spider and transfer them back to the wire racks. They will be cooked from the inside but not golden brown and crisp. Let the oil return to temperature before adding the next batch. The fries can be cooked to this stage and left to sit for up to 4 to 6 hours if you’d like to do this in advance. If you plan to serve immediately, keep the oil warm over low heat.
5. Preheat the oven to 400°F [200°C]. To make the filet mignon, pat the steaks dry with clean paper towels and season on both sides with salt and pepper.
6. In a large cast iron or stainless steel skillet over medium-high heat, melt the ghee. Add the olive oil and heat until the fat starts to smoke. Add the steaks and sear on one side for 5 minutes while using a large spoon to baste them with the hot fat in the pan. Flip the steaks and immediately transfer to the oven. Cook until the steaks reach the desired temperature (120°F [50°C] for rare or 130°F [55°C] for medium rare) as measured by an instant-read digital thermometer. To avoid overcooking, check the temperature after the first 5 minutes of cooking. Transfer the steaks to a baking sheet or large plate and let rest for 5 minutes before serving.
7. While the steaks are in the oven, heat the oil in the Dutch oven to 350°F [180°C]. Fry the potatoes, again in batches, until light golden brown and crisp, letting the oil return to temperature before adding the next batch, 4 to 5 minutes. Transfer to the racks and sprinkle salt on the hot fries. Toss to coat well.
8. Serve each filet mignon with a dollop of the smoky anchovy butter and the steak frites.

THE FLAVOR FILES

• If you want to air fry the frites, preheat your air fryer to 350°F [180°C]. Once the potatoes are coated with the cornstarch and dry, toss them in 3 Tbsp extra-virgin olive oil and cook them until golden brown and crisp, about 10 minutes.
• This is a good place to try out that jar of truffle salt you’ve been holding on to; sprinkle it over the hot frites. Garlic salt and other types of savory salts can also be used.