On bottom: the most common Seaiyou Kabocha, above: the sunshine kabocha
A lot of people recognize that winter squash are durable things, but you actually don't want them to be too fresh. Like an avocado, most "just picked" squash are not yet ready to eat. Kabocha in particular should should ripen 10-14 days after picking around room temeperature, and will easily develop another month stored in a cool dry place.
When picking one out, the squash should feel heavy and be without soft spots. The telltale sign of ripeness is the stem, it should be dry, withered a little and almost corky (see the pic), if not, it might need some time to ripen. You don't have to worry too much about the squash going bad before you get to it. It'll be a fine decoration until you get hungry.
The kabocha can be applied to most winter squash recipes, but the carbohydrates that develop lend themselves nicely to an old fashioned mash.
This is the what I used at last year's Pig Island event.
3 cups Roasted and cleaned kabocha squash
4 tbsps Butter
1/4 cup Heavy Cream
To roast the kabocha, remove the stem and carefully cut it in half and scoop out the seeds. (seed recipe) Using your hands, rub vegetable oil over the flesh and skin of the the squash. Season liberally with salt and pepper. Lay cut side down on tin foil and roast at 375 degrees for 30-40 minutes, or until a pairing knife inserted, comes out easily. Scrape out the meat of the squash and set aside.
Using a masher, or a sturdy whisk, crush the Kabocha with the butter and cream. (or for a finer puree, blend in a food processor) Season to taste and enjoy!
Notes: This mash goes great with fish. It's sweetness is the perfect complement to sea scallops with sage and brown butter. . .
yummy yummy stuff.