This dish owes its creaminess to a layer of tangy sour cream. Make it on a Sunday afternoon, and enjoy leftovers for another meal during the week. Or you can assemble the casserole, refrigerate overnight, and bake shortly before serving.
1 pound uncooked penne (tube-shaped pasta)
1 (26-ounce) jar fat-free marinara sauce
½ teaspoon salt
½ teaspoon freshly ground [...]