Step 1

Slice each tenderloin in half crosswise to create 4 steaks total. Pound each half to ¾-inch thickness. Using a sharp knife, cut ⅛-inch-deep slits spaced ½-inch apart in a crosshatch pattern on both sides of the steaks.

Step 2

Whisk lime zest and juice, garlic, honey, fish sauce (or liquid aminos), salt, and pepper together in a large bowl. Whisking constantly, slowly drizzle oil into lime mixture until smooth and slightly thickened. You can also do this in a blender. Transfer ½ cup lime mixture to a small bowl and whisk in the mayonnaise; set this aside. Place steaks in a large ziplock bag and add the remaining marinade (not the mayo marinade!!). Toss thoroughly to coat. Press out as much air as possible, and seal bag. Let steaks sit at room temperature for 45 minutes.

Step 3

For a charcoal grill: Open bottom vent completely. Light large chimney starter filled with charcoal briquettes (6 quarts). When top coals are partially covered with ash, pour evenly over half of grill. Set cooking grate in place, cover, and open lid vent completely. Heat grill until hot, about 5 minutes.

Step 4

For a gas grill: Turn all burners to high, cover, and heat grill until hot, about 15 minutes. Leave primary burner on high and turn off other burner(s).

Step 5

Clean and oil cooking grate. Remove steaks from marinade (do not pat them dry) and place over hotter part of grill. Cook, uncovered, until well browned on first side, 3 to 4 minutes. Flip steaks and cook until well browned on second side, 3 to 4 minutes. Transfer steaks to cooler part of grill, with wider end of each steak facing the hotter part of the grill. Cover and cook until meat registers 140 degrees, 3 to 8 minutes longer. Remove steaks as they come to temperature. Transfer to a carving board and let rest for 5 minutes.

Step 6

While steaks rest, microwave reserved sauce until warm, 15-30 seconds; stir in cilantro. Slice steaks against the grain into ½-inch-thick slices. Drizzle with half of sauce; serve, passing remaining sauce separately.