Remove steaks from the fridge 20–30 minutes before cooking to come to room temperature. Pat dry and season both sides with salt and pepper.

Dice potatoes into uniform 1/2-inch cubes so they cook evenly. Rinse and dry to remove excess starch; drying prevents sogginess.

Heat a large skillet over medium-high heat until hot. Add 2 tablespoons butter.

Sear steaks 2–4 minutes per side for medium-rare, depending on thickness. Use a thermometer to ensure precision (130–135°F for medium-rare). Transfer steaks to a plate and tent loosely with foil to rest.

In the same skillet, add the remaining 1 tablespoon butter and the diced potatoes. Spread them into an even layer and cook undisturbed for a few minutes to form a crust. Stir occasionally until potatoes are golden and tender, about 10–12 minutes total.

Push potatoes to the side and add 1 tablespoon butter with the minced garlic. Sauté garlic for 30–60 seconds until fragrant, making sure it doesn't burn.

Return steaks to the skillet for 1–2 minutes to rewarm. Spoon the garlic-butter over the steaks and potatoes to finish.

Remove from heat. Sprinkle with chopped parsley and an extra pat of butter if desired. Slice steaks against the grain for the best texture.

Plate potatoes alongside the steak or serve family-style straight from the skillet.