In a small bowl, combine the matcha with 60 ml of cream and whisk using a bamboo matcha whisk or a regular whisk until smooth and completely lump-free.

In a medium saucepan, add the chopped white chocolate, the matcha–cream mixture, the sugar, and the vanilla extract. Heat over low to medium heat, whisking constantly until the chocolate is fully melted and the mixture is smooth.

Once the chocolate has melted, whisk well, then remove the saucepan from the heat and let the mixture cool slightly.

In a stand mixer or using a hand whisk, whip the remaining 360 ml of cold cream until firm with soft peaks.

Gently fold the whipped cream into the cooled white chocolate–matcha mixture. Once fully combined, divide the mousse into serving glasses and refrigerate for about 2 hours, or until set.

Garnish with whipped cream before serving.