Perhaps you started seeing this squash in the last year of two. It was new to me but a friend told me how easy it is to use and I have made it a number of times.
What I like about this squash – Kabocha – is that you don’t have to peel the skin even though it looks pretty rugged. You can cook it with it on. (You can see in the photo how thin the skin is.) It doesn’t get tough. If you are going to leave the skin on scrub it good with a brush as it has a lot of irregularities and 
bumps for dirt to hide in.
Next you need to open the squash and clean out the seeds. To make it softer to cut you can stab it a few times with a big knife and place in the microwave for 5-7 mins. Be careful of the steam when you open it.
If you don’t want to use the microwave you can use a big knife and hit it with a mallet (meat tenderizer). 
Cut into smaller slices and then into 1″ cubes.
Chop an onion into small pieces. Also add a few chopped cloves of garlic and brown then on the stove or just add to it to the squash in a slow cooker. Add 2 cups of broth – your choice or water. Cook on medium – low for 4-5 hours. Again a microwave is faster but you may not want 
to use one.
Add whatever other spices you may want. To make it hot you can add chile pepper flakes and / or more garlic. You can add chai tea spices or a chai teabag or two. (Obviously remove this after an hour or so.) When it is done you can leave it chunky or take it out a few cups at a time and puree it in a blender.
Try adding a yam, carrots or celery.
This dish is good to nourish the Spleen and moisten the Lungs and Large Intestine. The garlic, onion and chile pepper are warming flavors, as are the chai spices, for the cold season.