In a medium bowl, combine 1 cup of finely chopped fresh parsley, 2 minced garlic cloves, the zest of 1 lemon, and 2 tablespoons of olive oil. Mix well until all ingredients are evenly distributed, creating a vibrant gremolata. Set aside for a moment to let the flavors meld while you work on the prawn broth.

In a saucepan, add prawn shells from 1 pound of jumbo prawns, 4 cups of water, a handful of fresh herbs (like thyme or bay leaves), and a sprinkle of salt. Bring the mixture to a gentle simmer over medium heat and let it cook for 20 minutes. Once done, strain the broth to separate the solids, resulting in a fragrant base for your dish.

Preheat your grill to medium-high heat, around 400°F (200°C). While it's heating, season the peeled jumbo prawns with salt and lightly brush them with olive oil. Place the prawns on the grill, cooking for about 3-4 minutes on each side. They should turn pink and opaque with a nice char, signaling they are ready to be taken off the heat.

In a shallow serving bowl, pour the hot prawn broth, ensuring an inviting pool of flavor at the bottom. Gently arrange the grilled prawns on top, showcasing their beautiful color. Spoon the gremolata over the prawns, allowing the fresh herbs and zesty garlic to brighten the entire dish.

Garnish the dish with fresh lemon slices and a few more sprigs of herbs for added color and freshness. Serve the Grilled Gremolata Prawns in Prawn Broth right away to ensure your guests can enjoy the delightful warm flavors while the prawns remain tender and flavorful.