Preheat the oven to 170 degrees C.
Rub the coconut oil into the flour and ground almonds.
Leave in the fridge for 30 mins.
Roll out and cut a circle shape.
Press the circles into the holes on a greased muffin tray.
Bake for around 15 mins. Then take out and leave to cool for a few mins before removing from the tray and leaving on a cooling rack.
Add the custard powder and sugar to a jug then slowly whisk in the custard powder. Add the vanilla essence.
Whisk over a low heat until thickened then leave to cool.
Spoon a tbsp of rhubarb on top of the custard.