Cook the penne rigate in a large pot of well-salted boiling water. Drain just before it's al dente and toss with a splash of olive oil. Warm the tablespoon of oil in a large pan over medium-high heat and cook shrimp and shallots (in batches, if necessary, to avoid crowding the pan), adding a large pinch of salt and stirring, for a minute. Add the wine and cook until it has nearly evaporated but just before it begins to color. Add the cream and pasta, stirring until the sauce is no longer soupy and coats the pasta (1 to 2 minutes). Add about 1/2 teaspoon kosher salt and the basil, toss, and serve.