For the cake :
4 eggs, separated
2 tablespoons butter, melted and cooled
6 tablespoons sugar
2/3 cup flour
3 tablespoons corn starch
1 tablespoon matcha (finely powdered green tea)
a good pinch of salt
For the filling:
I used chocolate cream cheese beat with powder sugar.
- Prepare the cake. Preheat the oven to 200°C (400°F) and line a 35-by-25-cm (14-by-10-inch) jelly roll pan with parchment paper.
- In a medium mixing bowl, combine the egg yolks with butter and sugar. Beat well. In another bowl, sift together the flour, corn starch, and matcha. Stir the flour mixture into the egg yolk mixture until just blended, try not to over mixing.
- Place the egg whites and the pinch of salt in a clean, grease-free mixing bowl, and whisk until stiff. Stir one third of the egg whites into the batter. Don't over mix it. The batter should looks creamy.
- Pour the batter onto the prepared pan or sheet, making sure it reaches the corners, and smooth out the surface gently with the spatula. Bake for 6 to 8 minutes, keeping a close eye on it, until just set; it should not color. (If you are overbaked, which I did for the first time, it won't be able to roll.)
- While the cake is baking, prepare the filling. Set aside.
- Once the cake is baked, you have to work quickly while the cake is still warm, otherwise it will be too stiff to roll. Slide the parchment paper and cake on a cold baking sheet or a tray.
- Cover with a clean dishtowel (or a fresh sheet of parchment paper) and flip cautiously onto your work surface. Remove the cold baking sheet or tray and carefully peel off the sheet of parchment paper on which the cake baked. The cake will now be upside-down.
- Spread the filling onto the cake, leaving a margin all around. Roll the cake tightly onto itself, starting from the edge closest to you. Wrap the rolled cake tightly and place it seam side down in the fridge to set for a few hours or overnight.