Pasta - Pasta with Sweet Potatoes (nice first course)

Cut sweet potato into 1/2" pieces.  Heat 2 T oil in skillet over medium low heat.  Add potatoes, 3/4 t salt, 1/4 t pepper.  Cook, covered, stirring occasionally, for 10 minutes.  Add 2 sliced shallots and 1 T chopped fresh rosemary.  Cook, uncovered, until potatoes are tender, 3-5 mins.  Toss with pasta and Parmesan.  Dollop with ricotta before serving.