Whisk together marinade ingredients.
Combine marinade and steak in a large ziplock bag. Seal and chill for 30 minutes, or up to overnight.
Combine all chimichurri ingredients in a blender or food processor, and pulse until smooth.
Preheat a an oiled skillet or grill to medium-high heat.
Sear steak for 6-8 minutes on each side until heavily browned on the outside and slightly pink in the middle.
Thinly slice steak across the grain and serve with chimichurri sauce on top.
