In a bowl, whisk together the beer, olive oil, soy sauce, minced garlic, ginger, chillies, pepper and coriander seeds.
Add the beef, coat well with the marinade, cover and refrigerate for at least 6 hours.
Heat a grill pan until very hot. Brush it with olive oil and then add the steaks and the garlic cloves.
Cook the minutes 3 minutes on each side to mark it nicely, then cook until done.
About 1 minute before the steaks are done, add the cayenne chillies to the pan.
Season with salt and pepper, wrap each steak with a strip of the banana leaf.
Arrange on a dish and top with the garlic cloves and the chillies, serve.