Press the kabocha through a strainer. Mix in the milk to make smooth.
Add all [A] ingredients into a bowl and mix well. When white and thick, add the kabocha mixture and vanilla extract.
Make a meringue with [B] ingredients. Whip lightly and add 1/3 of the granulated sugar. Mix well. Add the rest of the sugar in two batches. Whip until it forms peaks.
Mix in the vegetable oil into the bowl from Step 3.
Sift the dry ingredients into the bowl.
Add 1/3 of the meringue. Whip from bottom up, and mix while incorporating air.
Now using a rubber spatula, add the rest of the meringue in 2 batches.
Pour the batter into the mold. Smooth out the surface. Bake in 170°C oven for 35 to 40 minutes.
When done, flip it upside-down to cool. After it's cooled down, cover with a bag and let it moisten up.
Remove from mold when it's completely cooled down. Serve.
Here, I sliced the cake and wrapped it individually before forming them into a chiffon shape again.
Story Behind this Recipe
I combined my two favorite things - kabocha squash and chiffon cakes.
In Step 4, make sure to whip the meringue until stiff so that it won't drop even if the bowl is turned upside-down. If you add sugar from the beginning, the meringue won't form, so take care to add after whipping briefly.