Microwave method: microwave cacao butter and marshmallows in a large, microwave safe bowl at 15 second intervals until fully melted. Stir in between intervals, and keep an eye on it so it doesn't overflow.

Stovetop method: on low heat, melt marshmallows and cacao butter, stirring constantly. It can easily burn using this method, so keep an eye on it, and stir often.

Once the marshmallow and cacao butter mixture is melted, sift in matcha powder, add vanilla extract and stir to combine.

In a large mixing bowl, add rice crisp cereal, and fold in melted marshmallow mixture with a spatula until evenly combined.

Transfer mixture into an 8x8 square baking dish lined with parchment paper, and allow to cool and set for about 30 minutes. You can also pop into the fridge or freezer to speed up the process.

Once set, slice into 9 or 12 pieces and enjoy!