Pat your skirt steak dry and season both sides with salt and pepper.
Heat a cast iron skillet over medium-high and add olive oil.
Sear the steak for 2–4 minutes per side, depending on your preferred doneness.
Meanwhile, pulse all chimichurri ingredients in a blender or food processor — just enough to combine without losing texture.
Let the steak rest for 10 minutes. Slice against the grain and top with chimichurri.