Preheat your grill getting it ready for the steak. If you're using an indoor grill ensure you're using the exhaust fan.
Season the steak with chili powder, salt, and pepper, then gently place on the grill.
Grill the flank steak for 4-5 minutes per side for medium rare to medium (final photo is 145 degrees for medium at about 6-7 minutes per side for medium) 6-8 minutes per side for a medium well steak.
Once the steak is done remove it from the grill and allow it to rest for 10 minutes before slicing.
Squeeze the juice of a lime or lemon onto the steak before slicing.
Slice the flank steak against the grain and then cover with 1/2 cup of the chimichurri sauce.
Chimichurri Sauce
Finely chop the parsley and garlic using a knife and cutting board. You can also pulse in a food processor separately, but do not puree!
Place the parsley and garlic into a bowl and add in the remaining ingredients.
Mix until fully combined.
Use as desired and store leftovers in the refrigerator or freeze.
Notes
You will have leftover chimichurri sauce, which is calculated in the nutrition information.