So whan I was in the Philippines I eventually figured out that a lot of the vegetable dishes they had there tasted better, were cheaper, and were less likely to get me sick compared to meat based dishes. I formed a love of squash cooked in this fashon.
The first thing you will want to do is to remove the seeds form your squash and peel it while it is still raw. Peeling raw squash is not the world's easiest task so realize that this will take a while, I've fund that it is easiest to do this with butternut squash because of their unifirm shape and small amount of seeds. Once you're done with that chop your squash into cubesand set aside. you should have enough to fill a large mixing bowl.
Once you've prepared your squash you can move on to choping your onion and cooking in a large pot until translucent, this is also when you put in our garlic if desired. Once your onions are translucent throw in all of your squash and dump in your can of coconut milk, there should be enough coconut milk to cover everyting in the pot, if not you can water it down a bit.
You'll let that all simmer until all of your squash cubes are soft. When this happens you will then need to mash about half of the squash. Ideally you would own a potato masher to do this with but I don't have one of those so I ended up breaking a wooden spoon by pushing the squash cubes into the side of the pot. As you do this the coconut milk will turn orange.
Once you are done with that its all done, because this id Filipino food it would be criminal for you to eat it without rice so put as much as you want on rice then stick the rest in the fridge because this makes a really big batch, be prepared to eat this every day for a week.