In a large cast iron skillet, melt the butter over medium heat. When it starts to foam, add the your shrimp.
Cook for 3 minutes. Watch your heat, you may want to turn it down as your pan becomes hotter.
Flip the prawns and add the garlic. Cook an additional 3 minutes, stirring the garlic to ensure it doesn't cook to fast and burn.
Squeeze lemon juice over the prawns and garlic. Remove the prawns. Continue cooking the garlic (if needed) till you get a beautiful golden caramelized color.