1
Blend the nuts and oats to a course flour in a food processor or blender.
2
Add the remaining ingredients and process until the mixture looks moist and just starts lumping together.
3
Line a small tray with baking paper – a regular bread tin works well. Squish the mixture into the tin to form an even base.
4
Melt the white chocolate and oil. You can do this in a small heatproof bowl placed over a pot of simmering water, or use a microwave.
5
Spread half of the chocolate evenly over the base.
6
Using a fork, whisk matcha into the remaining chocolate and drizzle it over the base. Drag a toothpick between the white and green to create patterns.
7
Let firm up in fridge for 10 minutes.
8
Cut in squares (or triangles as in the image) using a big sharp knife.
9
For neatest results, pour hot water on the knife before cutting, and wipe knife between cuts. Store in an airtight container in the fridge.