Slice Against the Grain: Trim only large hard pieces of fat from the steak. Slice into thin fajita strips against the grain to ensure every bite stays tender and juicy.
Blend the Marinade: Add orange juice, lime juice, oil, garlic, onion, cilantro, kosher salt, black pepper, cumin, smoked paprika, onion powder, garlic powder, Mexican oregano, and achiote paste to a blender. Blend until completely smooth.
Check the Flavor: Taste the marinade before adding it to the steak. It should taste bold, savory, garlicky, and slightly salty since toppings and sides will mellow the final flavor.
Marinate the Steak: Place the sliced steak into a large bowl or zip-top bag. Pour the marinade over the meat and massage thoroughly to coat every piece. Cover and refrigerate for 8-20 hours.
Prepare for Cooking: Remove the steak from the refrigerator 30 minutes before cooking to encourage better browning and more even cooking.
Heat the Cooking Surface: Preheat a grill, Blackstone, cast iron skillet, or stainless-steel skillet over high heat until very hot.
Cook in Batches: Add steak in a single layer and cook in batches if necessary. Avoid overcrowding the pan to ensure proper searing and caramelization.
Sear to Perfection: Cook for 2 to 4 minutes total, stirring occasionally, until browned with charred edges while remaining juicy inside.
Avoid Overcooking: Remove the steak once it is browned and cooked through but still tender. Slight pinkness is acceptable depending on preference.
Rest the Steak: Let the steak rest for 5 to 7 minutes before serving to help retain its juices.
Finish the Steak: Lightly toss the steak with the butter mixture to add shine, moisture, and an extra layer of savory flavor.
Serve and Enjoy: Serve immediately in tacos, burritos, burrito bowls, nachos, fajita plates, salads, or alongside rice and beans.