Transfer the butter mixture onto a piece of plastic wrap. Roll it into a log shape, twisting the ends to seal. Refrigerate for at least 30 minutes to firm up.

Cooking the Pommes Frites

Prep the Potatoes

Peel the russet potatoes and cut them into thin strips (about 1/4 inch thick) to make fries.

Soak the Potatoes

Place the cut potatoes in a bowl of cold water and let them soak for at least 30 minutes. This helps to remove excess starch and achieve crispiness.

Heat the Oil

In a large pot or deep fryer, heat the vegetable oil over medium-high heat until it reaches 350°F (175°C).

Fry the Potatoes (First Fry)

Drain the soaked potatoes and pat them dry with paper towels. Fry the potatoes in batches for about 4-5 minutes until they are soft but not browned. Remove and drain on paper towels.

Fry the Potatoes (Second Fry)

Increase the oil temperature to 375°F (190°C). Fry the potatoes again in batches for an additional 3-4 minutes until they are golden brown and crispy. Drain on paper towels and season with salt.

Cooking the Steak

Season the Steak

Pat the hanger steak dry with paper towels. Season both sides generously with salt and black pepper.

Cook the Steak

Heat olive oil in a skillet over medium-high heat. Once hot, add the steak and sear for about 4-5 minutes on each side for medium-rare, or until desired doneness is reached.

Rest the Steak

Remove the steak from the skillet and let it rest for 5 minutes before slicing.

Assembly

Serve

Slice the steak against the grain. Serve it alongside the crispy pommes frites and a generous dollop of the Cajun compound butter on top of the steak.