Preheat the oven to 425˚F.
Cut the potatoes into thin wedges and spread out on a parchment-lined baking sheet.
Drizzle with oil and toss with your fingers to coat. Sprinkle with salt.
Roast for 20-30 minutes, turning once or twice, until golden.
Meanwhile, sprinkle your steak with salt and if it came from the fridge, let stand at room temperature for 10-15 minutes.
Heat a drizzle of oil in a heavy ovenproof skillet set over medium-high heat.
Cook the steak for 4-5 minutes, or until deep golden on the bottom, then flip and transfer the pan to the oven (alongside the potato wedges) for 10 minutes.
Let rest for 5-10 minutes before thinly slicing across the grain.
Place the skillet back on the stovetop, add the butter and flour and whisk to combine.
Whisk in the stock, stirring to loosen any browned bits on the bottom of the pan.
Bring to a simmer and cook for a few minutes, adding more stock if it’s too thick.
Serve the gravy over the fries, sliced steak and cheese curds.