Preheat the oven to 340°F (170°C).
Brew Japanese hojicha leaves. Adjust the amount of tea leaves for a stronger flavor, if desired. Let it cool completely before using.
In a medium mixing bowl, whisk together the egg yolks and vanilla extract. Add 25g of sugar and whisk until the mixture becomes pale and slightly thick (about 3 minutes). Pour in the oil and cooled hojicha, then whisk until combined.
Sift the cake flour into the yolk mixture and whisk until smooth and free of lumps. Set aside.
For the Meringue: Beat the egg whites in a clean bowl on low speed until frothy. Gradually add 50g of sugar while increasing to medium speed. Continue beating until stiff, glossy peaks form.
Add about half of the meringue into the yolk batter and gently fold until mostly combined. Add remaining half, careful not to over mix.
Pour batter into an ungreased 7" chiffon cake pan. Bake immediately for about 40mins.
Invert the pan immediately after baking and let the cake cool upside down to maintain its height. Once cooled, carefully remove it from the pan.
Dust with powdered sugar and serve with fresh fruit and whipped cream.
