Cut 100 g kabocha squash into 5 mm thick wedges, without peeling, and arrange them in a spiral pattern in a frying pan. Cut off any parts that overlap.
Peel 50 g kabocha squash, cut it into 5 mm pieces and put in a heatproof container (such as a silicone container).
Add 2 teaspoons water to the container, cover with plastic wrap or a lid, and microwave for one and a half minutes.
Take off the plastic wrap (or the lid) and mash the kabocha squash with a fork or potato masher.
Put the pancake mix, egg, sugar, milk and mashed kabocha squash in a bowl and mix well with a whisk.
Put 5 g butter in a separate heatproof container, microwave for about 30 seconds to melt the buter, and stir it into the Step 5 mixture.
Take the kabocha squash out of the frying pan in Step 1, and add the sugar, cinnamon and butter to the pan.
Heat the pan over low heat, stir with a spatula until the butter is melted, then turn off the heat.
Rearrange the kabocha squash from Step 7 in the frying pan in the same way as before.
Pour the batter from Step 6 over the kabocha squash.
Cover the frying pan with a lid, and cook over the lowest possible heat for 8 minutes.
If using a gas flame, it should be about this strength.
When the center of the cake puffs up, turn off the heat. Leave the frying pan as is for 5 minutes with the lid on.
Remove the lid, and run a spatula around the edges so you can remove the cake easily.
Invert a large plate on top of the frying pan. Holding the frying pan and the plate, invert the cake onto the plate.
Story Behind this Recipe
I wanted to try making a cake like "Apple Cake Made With Pancake Mix" (Recipe ID: 1379912), using kabocha squash instead of apples. The first time I made it, it burned, so the next time I halved the amount of batter and didn't cook it as long, and it turned out well.
Adjust the cooking time in Step 3 according to the container you are using. Using a glass lid on the frying pan makes this easier to make, since you can see the inside. Keep an eye on the cake, and adjust the cooking time of the cake according your type of frying pan and heat source.