Preheat oven as instructed in pizza crust recipe or package.
Cut the squash in half and deseed.
Put a little olive oil in your hands and cover the squash halves inside out in olive oil.
Put in oven for 45-60 minutes depending on size of squash (insert a wooden pick in the squash, once soft as avocado, the squash is ready)
Peel and slice onions in thin stripes.
Heat a little olive oil over medium heat in a medium sized pan and once hot add onions.
Turn down heat to low and fry your onions until caramelized stirring occasionally to prevent from burning. Onions are caramelized when very very soft and caramel colored (this can take up to 45 minutes).
Once squash is done take out and let cool as much as necessary to be able to take it into your hand and scrape out the flesh. I usually wait until I can hold the squash with my dishwashing gloves. Leave oven on at 350 F.
Take out your pizza crust and cover evenly with cheddar cheese. Spread out flesh of squash on pizza and cover evenly with caramelized onions.
Salt and pepper to taste and cover with Parmesan cheese.
Bake for as long as pizza crust instructions recommend (usually 8-12 minutes).