Preheat your oven to 175°C (350°F) and line an 8-inch and a 7-inch cake tin with baking paper and acetate.

In a microwave-safe bowl, combine the milk and softened unsalted butter, heating for about 30 seconds until melted. Allow it to cool slightly.

In a separate bowl, beat the eggs and caster sugar until the mixture is pale and has tripled in volume.

Gently fold in sifted all-purpose flour and matcha powder until just combined.

Pour the batter into the 8-inch tin and bake for 15-20 minutes or until a toothpick comes out clean.

While the cake bakes, soak gelatin leaves in cold water for about 5 minutes to soften.

In a microwave-safe bowl, combine melted white chocolate, heavy cream, and a splash of cold water, microwaving for 90 seconds until smooth.

Once melted, squeeze excess water from the gelatin and stir it into the white chocolate mixture until fully dissolved.

Let this mixture cool to room temperature before preparing the whipped cream.

In a large bowl, whip the heavy cream with powdered sugar until it reaches stiff peaks.

Carefully fold the cooled white chocolate mixture into the whipped cream.

Pour this mousse over the cooled sponge cake in the 7-inch tin, smoothing the top gently with a spatula.

To make the matcha mousse, combine matcha powder with a small amount of cold water and cream in a bowl, heating briefly in the microwave.

Soak gelatin as before, adding it to the warm matcha mixture while stirring until fully dissolved.

Once cooled, fold this mixture into whipped cream.

Spoon the matcha layer over the white chocolate layer in the 7-inch tin, leveling the top.

Cover the cake and place it in the freezer for at least 4 hours or until all layers are fully set.

Once set, remove it from the tin and dust the top with matcha powder before serving.

Slice with a hot knife for clean edges and serve chilled.