Bring the clam juice and orange juice to a boil over high heat in a 12-inch skillet until the mixture is reduced by half, about 5 minutes. Meanwhile, peel and devein the shrimp (to save time, look for "easy-peel" shrimp, which has already been deveined). With a spatula, scrape the reduced sauce into a small bowl and set aside.

Without rinsing the pan, return it to high heat and add the butter and garlic; cook until the garlic starts to sizzle, about 15 seconds. Add the shrimp and saute until it just starts to lose its raw color, 2 to 3 minutes, sprinkling lightly with salt and pepper to taste. The pan will start to darken as the sugar from the sauce cooks; don't worry, this will just add more flavor to the finished sauce. Add the reduced sauce and bring to a simmer. Stir in the Pernod or vermouth and the basil. Remove and discard the garlic cloves, adjust the seasonings, and serve. Angel hair pasta or rice makes a nice accompaniment.