Preheat oven to 400°F. Peel, de-vein, and rinse the shrimp. Pat dry and season with salt and pepper. Place in the fridge until ready to grill.
Trim the top of the garlic head off, but leave the garlic intact. Drizzle generously with olive oil. Roast the garlic in oven for about 10-15 minutes or until slightly tender and fragrant. When ready, remove from the oven. Let cool briefly. Peel and crush or chop the roasted garlic as finely as possible.
In a small bowl, combine the roasted garlic with the remaining sauce ingredients of cilantro, lemon juice, white wine, olive oil, and chili flakes. Whisk together and set aside.
When ready, lightly oil and heat a cast iron grill or griddle to medium-high. Dress the prawns with a little olive oil and grill for 3-4 minutes on each side. Remove from the grill and place on a serving platter. Serve hot with sauce on the side for dipping. Enjoy!