Combine the melted butter, garlic, cumin, paprika, onion and cinnamon and set aside.
Combine all the ingredients for the chimichurri, mix well and set aside.
Preheat your BBQ grill to high. If using charcoal make sure that the grill is not too close to the coals but is still at a very hot temperature.
Split the prawns down the middle, cutting from the top side with a very sharp knife and set, the meat side up on a baking tray or plate.
Brush the prawns with the melted butter mixture on the meat side.
Placing the prawn's shell side down, meat side up on your grill, and brush well with the chimichurri mix.
Allow cooking for 4-6 minutes, depending on your grill. Once the flesh turns white and is no longer opaque, the prawns are ready.
Remove from the heat, apply a little more chimichurri and serve with grilled lemon wedges for acidity.
The original recipe calls for King Prawns and these can be used. However, bear in mind these are bigger prawns and you’ll need to increase the number of ingredients to cover the extra size.
You can remove the heads if you wish. However, they plate nicer with the head still attached.