Warm the butter in a small pan over LOW heat, until melted. Add the rub and stir to mix well. Set aside to cool slightly.
Heat up a pan (cast-iron preferred) on HI heat.
Place the prawns into the butter mix and stir gently to coat.
When the pan is heated, add the olive oil. Swirl the olive oil to coat the pan evenly, then add the prawns.
Cook the prawns, for about 1 – 2 minutes on each side or until they are cooked.
Turn the heat to LOW and pour in the remaining butter mix, let it sizzle until the butter is slightly browned.
Turn off the heat and plate up.