This moist honey sponge cake was introduced to Japan by Portuguese merchants in the 16th century. It is now a popular street snack and festival treat in the city of Nagasaki (which, in the 16th century, was the only port open to foreign commerce). Nowadays, there are more variations to castella such as green tea castella and honey castella.
I found this recipe in Pichet Ong's cookbook The Sweet Spot and I decided to give to my classmate Hanako Saeki, who had just returned from visiting her family in Japan for winter break.
1/4 c. canola, vegetable, or other neutral oil, plus more for greasing the pan
1 1/2 c. all-purpose flour
1/2 tsp. salt
7 large eggs
3 large egg yokes
1 1/2 c. sugar
1/4 c. honey
1. Preheat the oven to 350 F. Generously grease a 9 x 13-inch cake pan and set aside.
2. Sift together the flour and salt and set aside.
3. Put eggs, yolks, sugar, and honey in the bowl of an electric mixer and set over a saucepan of simmering water. Whisk constantly until the sugar is completely dissolved and the mixture is warm to the touch, about 10 minutes.
4. Fit the bowl into the mixer and whick at medium-high speed until the misture is pale yellow, thick and completely cool, about 10 minutes. Gently fold in the dry ingredients. (Add the dry ingredients slowly because it is hard to fold it in completely without deflating the egg mixture.)
5. In a small bowl, whisk together 1 cup of the batter with the oil until smooth and homogenous. Add the oil mixture into the remaining batter in a slow, steady stream, folding continuously.
6. Transfer to the prepared cake pan. Bake for 15 minutes, then turn the heat down to 300 F and bake until a tester inserted in the center comes out clean, about 45 more minutes. Cool completely in the pan on a rack.
7. Serve the cake alone or top each slice with a dollop of Concord Grape Preserves, if desired.