For the balls, whizz the porridge oats in a food processor or blender until a fine crumb is formed.
Add the remaining ingredients and pulse until well combined and it forms a sticky meal.
Roll into balls and refrigerate until ready to eat.
For the icing, cream the coconut oil with an electric mixer until smooth, then beat in the powdered icing sugar and vanilla. If it’s too thick add a very small amount of water and beat again. Add to a piping bag and pipe in tennis ball swirls onto the matcha coconut energy balls. Store in the fridge.