To make the chimichurri sauce: In a mortar and pestle or food processor, mash or mince the garlic. Add the cilantro, parsley, thyme, and oregano and continue mashing until the herbs are coarsely ground. Mash in the red pepper flakes, then the lemon zest and vinegar. Slowly drizzle in the oil while mixing. Season the chimichurri sauce to taste with salt and pepper.
(14- to 16-ounces each) T-bone steaks
To grill the steaks: Prepare a barbecue for medium-high heat. Sprinkle the steaks with salt and pepper.
Set the steaks, fat-side down, on the grill. Grill for about 4 minutes, or until the fat is rendered and golden brown. Lay the steaks, cut-side down, on the grill and cook to your desired doneness, about 4 minutes per side for medium-rare doneness.