Preheat the oven to 180 degree Celsius. Grease 3 ramekins with butter, add pistachios to the bowl, swirl it around to coat the bowl.
Beat together egg, sugar and corn flour until light and fluffy. Add milk, essence and avocado and beat it again. Pour the mixture into the prepared ramekins. Place the ramekins in a roasting tin fill it half way through with boiling water.
Bake it in the preheated oven for 30 minutes or until the top of the pudding is firm to touch and a skewer inserted comes out clean.
Serve with a selection of fresh fruits like kiwi, melon or grapes.