I learned how to make this dish from a vegetarian friend I met in college. He showed me how easy it was to cook up, and how delicious it was to eat and I've never lost my love for it. It's especially good in the winter, when Butternut Squash is a hearty and fresh vegetable. I'm making this tonight!
Take a big butternut squash, wash the outside and split in half. Scoop out the seeds and fibrous insides, and dice into about 1-2" pices.
Melt a half a stick of butter in a large heavy iron skillet, sprinkle with salt and sautee the squash over med-high heat for about 5 min., stirring and coating the pieces. Cover with a lid (preferably tight), turn down heat to low and simmer for 15 minutes.
Stir, and add one 15 ounce can of whole peeled tomatoes (including juice). Snip the tomatoes with scissors until they are small pieces the size of the squash. Stir, add a small amount of grated nutmeg and cook uncovered on low till ready to serve. Don't over cook. The squash should be tender but still firm.
Grate fresh Parmesean or Adagio cheese over the squash, cover, turn off heat and leave till the cheese melts.
Dish into bowls for serving.