Chop up the kabocha squash and microwave to soften. If your oven has a "cook vegetables" setting, please use that.
When the kabocha is cooked, preheat oven to 180℃.
Combine the hot kabocha from Step 1 and the butter in a bowl. Mash and blend with a hand mixer. You can also use a blender or a food processor.
(If you don't have any electric appliance as above, please mash and mix the kabocha manually with a whisk.)
Measure and add all the other ingredients into the bowl. There's no need to sift the flour.
Line the cake pan with a sheet of parchment paper, and pour in the batter. Bake for 45 minutes in the preheated oven.
After 30-35 minutes, check on the cake. Cover it with aluminum foil before it burns.
When done, test the cake with a skewer and make sure it comes out clean. Done. Wait until it cools down, and remove from the pan.
For best results, chill in the fridge before serving.
(You can actually make this in a rice cooker. Pour the batter into the rice cooker, and switch it on. When done, test it with a skewer. If it's not done, then cook it again.)
(Please remove the skin of the kabocha squash if its flavors bothers you. Without the skin, the cake becomes beautifully orange.)
Story Behind this Recipe
My regular recipe for kabocha squash cake uses tons of butter. One time, I tried making that cake with tofu instead of butter, and it turned out quite nicely! Since then, I often make this cake when the kabocha are in season.
You don't need to be too precise when measuring out the ingredients. One time I used drained yogurt when I didn't have tofu, and the resulting cake tasted nice and light. The butter is mostly for the flavor. So it's optional!! This cake is quick and easy; you won't have too many dishes to wash, either.