Let the marinade come to room temperature before preparing the dish. Using a large spoon, skim off almost all of the oil from the top of the marinade. Put the marinade into a large skillet, then add the shrimp. Cook over medium heat just until the shrimp turn pink and opaque, about 3 to 4 minutes, then turn the shrimp, add the potatoes, then cook until the potatoes are heated through, about 2 to 3 more minutes. Season to taste with salt and freshly ground black pepper.
Usual garnish is a wedge of lemon and a sprig of parsley.
Have plenty of cold beer handy, and watch your guests moan with pleasure.