Combine oil, vinegar & Doxy's Smoky Chipotle Starter in a zip-top bag. Swish a bit to combine. Add flank or skirt steak, seal & make sure the steak is covered in marinade. Refrigerate for 30+ mins.
Grill for approximately 6-7 minutes per side, or until desired temperature.
Thinly slice against the grain and serve on fajita size tortillas with Pico de Gallo, Guacamole, Sour Cream and grated Cheese. (See other Doxy's guides.)