Step 1: Preheat your oven to 350. Spray a 9” pan (or springform pan for easier removal) with nonstick cooking spray and line with parchment paper.
Step 2: In a bowl, combine all dry ingredients. Add water, canola oil and vinegar and whisk until smooth. Pour into your pan and bake for 8-11 minutes. Remove cake from oven and set aside to cool. Do not remove your cake from the pan.
Step 1: Prepare gelatin powder for use by soaking it in 6 tablespoons of cold water for 5 minutes. Then, microwave for 20 seconds.
Step 2: Add white chocolate, butter and rum. Stir with a spatula until chocolate and butter are melted.
Step 3: Add white chocolate, butter and rum. Stir with a spatula until chocolate and butter are melted.
Step 4: In a large mixing bowl, add remaining cream and sugar. Using an electric mixer, beat until thick peaks form. Gradually mix whipped cream into matcha cream mixture using a spatula.
Step 1: Using a spatula, spread mousse over your cake. Refrigerate or freeze for 4 hours. Garnish with sifted matcha powder then slice and serve.