Line a slice tin with baking paper allowing it to flow over the edges.

Pulse all base ingredients in a food processor or high speed blender until well combined. Add a teaspoon of water at a time, if need be, until the mixture starts to stick together.

Transfer the mixture to the lined tin and press down evenly to form a base, place in the freezer to set.

Wash the food processor and make sure it’s completely clean of previous mixture. Place in all the icing ingredients and blend/pulse until smooth and creamy.

Remove tin from the freezer, pour the icing on top, sprinkle with a little extra lemon rind and store in the fridge. Best eaten once the icing has firmed.