Prepare the grill for indirect cooking over medium heat (180°C to 230°C).
Remove the loose, papery outer skin from the heads of garlic. Using a sharp knife, cut about 1 centimetre off the top to expose the cloves. Place each garlic head on a large square of heavy-duty aluminum foil and drizzle 1 tablespoon of the oil over the top of the cloves. Fold up the foil sides and seal to make a packet, leaving a little room for the expansion of steam. Brush the cooking grates clean. Grill the packets overindirect medium heat, with the lid closed, until the cloves are soft, 45 minutes to 1 hour. Set aside to cool.
Place the rosemary, parsley, pine nuts and chile peppers in a food processor. Process until the herbs are finely chopped. Squeeze out the garlic cloves into the food processor, being careful not to add any of the papery skin. Process just to incorporate the garlic. Transfer the mixture to a medium bowl and add 60 millilitres oil with lime zest, salt and pepper. Mix well to create a paste.
Spread the paste evenly on both sides of the steaks. Cover with plastic wrap and refrigerate for 2 to 4 hours. Allow the steaks to stand at room temperature for 15 to 30 minutes before grilling.
Change the method and increase the temperature of the grill to direct cooking over high heat (230°C to 290°C). If you’re using a charcoal grill, keep a small part of the charcoal grate clear of briquettes as a safety zone of indirect heat.
Grill the steaks over direct high heat, with the lid closed, until cooked to your desired doneness, 6 to 8 minutes for medium rare, turning once or twice (if flare-ups occur, move the steaks temporarily over indirect heat). Remove from the grill and let rest for 3 to 5 minutes. Serve warm.