How to Make It
In a food processor, pulse the garlic until finely chopped. Add the parsley, oregano, thyme, rosemary, sage and crushed red pepper and pulse until the herbs are finely chopped. Add the olive oil and pulse to blend. Season with salt and pepper and transfer the chimichurri to a bowl.
Light a grill or heat a grill pan. Season the steaks with salt and pepper and grill over moderately high heat, turning once, until well browned outside and medium-rare within, about 10 minutes total. Let rest for 5 minutes.
Meanwhile, in a medium saucepan, heat 1 inch of vegetable oil to 350°. Fry the potatoes in batches until golden and crisp, about 4 minutes per batch. Using a slotted spoon, transfer the potatoes to paper towels to drain. Season with salt. Serve the steaks with the potatoes and chimichurri.