Cut the winter squash in half an inch slices and add salt and pepper.
Preheat oven and bake for 25 minutes.
Then, add tomato sauce, cheese and oregano to some of the slices, cheese and onions to some others (as you like) and take to oven again for just a couple of minutes (just until the cheese melts).
If you don't like the onions so raw, you can boil them for 5 minutes before adding them to the pizza.
Any kind of pizza you like can be cooked this way. Instead of the regular pizza dough, you'll be using the winter squash!