Combine parsley, garlic, oregano, jalapeno, lemon zest, juice and salt and pepper in a small bowl.
Add olive oil (I usually start with ¼ cup) and stir. You want a consistency that is similar to a pesto. I usually like to see a little olive oil swimming in the chimichurri.
In a large skillet, heat 1 tbsp of grapeseed oil over high heat– you’ll need an oil with a high smoking point with a neutral flavour. That is why I prefer to use grapeseed oil.
Add your steaks, and cook according to preferences. Depending on the size of the steak, this could be anywhere from 3 minutes, to 8 minutes per side. As a general guide, I tend to wait until I see blood appear on the top side of the steak before I flip it. Do not flip the steak more than once, otherwise, it’ll become tough.
Let the steak rest for 5 minutes, before slicing it into pieces.
Serve with the chimichurri.