Green Tea Souffle Swiss Roll

Recipe from Okashi by Keiko Ishida
Makes one 28cm x 28cm (11") flat square pan

1 egg
3 egg yolks
35g unsalted butter
60g pastry flour, sifted twice (I used cake flour)
60g milk
3 egg whites
85g castor sugar
1tsp vanilla extract (optional if using green tea powder)
5g green tea powder, sifted together with the flour (omit if making vanilla swiss roll)

Filling:
120g red bean paste
100g (single) whipping cream
2tsp icing sugar

1. Preheat oven to 180 degrees celsius. Line cake pan with parchment paper.

2. Combine egg, egg yolks and vanilla extract in a small bowl and beat lightly. Set aside.

3. Place butter in a small saucepan and heat gently until melted. Add flour to melted butter and cook through. Transfer butter-flour mixture into a bowl, then add egg mixture from (2), a little at a time. With a spatula, mix into a smooth batter. Add milk and mix to incorporate. Strain batter and set aside.