Preheat your oven to 425℉ or air fryer to 400℉. Line a baking sheet with parchment paper.
Toss the potatoes in the oil and then the seasonings to coat all. Roast for 15 minutes then flip and roast until golden brown and crispy. For the air fryer, roast for 10 minutes, flip and roast for another 7 minutes.
Steak:
Heat a large pan grill or work in batches in a smaller pan on medium high (you don't want to overcrowd the pan with the meat because it won't sear properly). Add 1 tbs butter to the pan to melt. Then add in the meat - cook for a few minutes per side to get a nice sear. Then add in the garlic and remain butter. Toss the meat with the garlic for a few minutes and remove to plate.
Sauce:
Whisk together all ingredients and taste to see if needs adjustment. Drizzle on the steak and potatoes and enjoy!