Grease a loaf pan with butter, dust it lightly with flour, and tap out the excess. Chill the prepared pan in the refrigerator while you make the batter. Preheat the oven to 392°F (200°C).

Roughly chop the mixed nuts and set them aside. Finely chop the white chocolate, place it in a heatproof bowl, and melt it over a bowl of hot water. Remove from the heat and let it cool slightly.



In a separate bowl, whisk together the cake flour, hojicha powder, and baking powder. Sift the mixture twice so it is evenly combined and lump-free.



Place the softened butter in a large bowl and beat until smooth and creamy. Add the granulated sugar in 4 additions, mixing well after each one, then continue beating until the mixture is pale and fluffy, about 8 minutes.



Crack the eggs into another bowl and beat just until smooth and fluid. Add the eggs to the butter mixture in 5 to 6 additions, beating well after each addition so the batter stays emulsified.



Mix in the vanilla oil, then add the melted white chocolate and stir until the batter is smooth and evenly blended.


Add the sifted dry ingredients all at once and gently fold with a spatula until no dry streaks remain. The finished batter should look smooth and slightly glossy.



Transfer the batter to the prepared pan and spread it evenly. Tap the pan lightly on the counter to release large air bubbles, then sprinkle the chopped nuts over the top.



Reduce the oven temperature to 356°F (180°C) and bake for about 43 minutes, or until a skewer inserted in the center comes out clean. Once baked, gently drop the pan once on the counter to minimize shrinking, then let the cake cool in the pan for 15 minutes.



Unmold the cake while it is still warm. Wrap it tightly in plastic wrap twice and let it rest at room temperature for 3 to 6 hours before slicing for the best texture and flavor.


