Start by cleaning the prawns and patting them dry.
In a large bowl, combine the plain flour, paprika, chilli powder, garlic powder and salt. Mix well and then add the prawns, toss to coat them, and set aside.
In a large pan, melt the butter over a very low heat. Once melted, add the garlic and cook until aromatic and lightly golden, which should take about 2–3 minutes. Now add the tequila and agave syrup and cook for 1-2 more minutes before pouring the sauce into a clean bowl.
Add the olive oil to the same pan and, once warm, add the prawns in a single layer (cook in batches if the pan is too small). Cook them for about 2 minutes on each side, until nicely crisp and browned.
Pour the garlic butter sauce back into the pan and mix with the prawns. Cook for another minute, but be careful not to overcook the prawns.
Season with salt and pepper to taste, then squeeze the fresh lemon juice all over the prawns. Garnish with the chopped parsley and serve with fluffy rice.