Melt all but 2 tablespoons of the butter in a medium saucepan over medium-low heat without boiling, about 4 minutes, and skim off any foam that rises to the surface. Remove from the heat and set aside.
Melt the remaining 2 tablespoons butter over medium heat in a medium pan. Cook the garlic, stirring, until fragrant, 1 minute. Add the prawns and cook, stirring frequently, until starting to turn pink, about 2 minutes. Pour in the wine and cook, stirring, until the liquid is nearly completely evaporated, about 3 minutes. Pour in the lemon juice and cook 1 minute longer. Stir in the salt and clarified butter and remove from the heat.
Spoon the prawns into a small baking dish. Stir in the parsley and pour the melted butter from the pan over the prawns just to cover. Reserve any remaining butter in the refrigerator. Chill the prawns until the butter is solid, 2 hours.
Pulse the prawn mixture in a food processor until pureed. Return the mixture to the baking dish. Warm the refrigerated reserved butter in the microwave just until liquefied, about 10 seconds. Pour over the prawns to cover and refrigerate 3 hours or overnight.
Remove the dish from the refrigerator 1 hour before serving. Spread on crackers or toasted baguette slices and garnish with additional parsley.