Add all of the slice ingredients into a food processor and blitz to combine. The mixture should be sticky and still slightly chunky.
Transfer the slice into a square baking dish lined with baking paper and flatten it with your hands.
Place the baking dish into the fridge for 10 minutes.
Prepare the chocolate drizzle by melting the chocolate and coconut oil in the microwave or over a double boiler.
While the chocolate is melting, remove the slice from the tray and cut it into 8 pieces.
Drizzle some chocolate over each slice and place back into the fridge for 15 minutes, until the chocolate is solid.
Store in an airtight container for up to a week.