Penne with Pumpkin or Squash

I love filled pasta, but I rarely have the time or energy to make it. So, when I became enamored of pasta con zucca—a ravioli-like affair stuffed with the Italian equivalent of pumpkin—I created this alternative, which is not quite as elegant but tastes just as good. If you cannot find a small pumpkin—the only kind whose flesh is dense enough for this d…