2) Meanwhile, combine all the other ingredients except the butter in a large mixing bowl and mix well. Drain the penne well using a colander and add to the ingredients in the mixing bowl, tossing to combine.
3) Divide the pasta mixture among 6 shallow ceramic gratin dishes (375 to 500ml capacity). Dot with butter and bake until bubbly and brown on top, 7 to 10 minutes. Serve hot.