Cut the picanha into 1-inch-thick steaks, slicing against the grain. Rub the lime juice evenly over both sides of each steak.
Season generously on both sides, including the fat cap. Place the steaks in a zip-top bag and refrigerate for at least 4 hours.
Remove the steaks from the refrigerator 45 minutes before cooking. Shape each steak into a “C” with the fat cap on the outside and skewer to hold the shape.
Preheat the grill to 350°F. Place the skewered steaks on the indirect side of the grill and cook for about 5 minutes per side.
Add mesquite chunks to the direct side of the grill and let them catch fire. Once they’re burning, move the steaks directly over the heat and sear for about 2 minutes per side, or until the internal temperature reaches 125°F for medium-rare.
Let the steaks rest for 4–5 minutes. Remove the skewers and serve with chimichurri sauce.
Chimichurri
In a bowl, combine all chimichurri ingredients and mix well. Refrigerate for at least 2 hours (or overnight) to enhance flavors