Wash the navel oranges and place into a large pot.
Cover with water and bring to the boil on the stovetop for 2 hours (add more water during this time).
Remove the oranges from the water and allow to cool completely (they'll be nice and soft).
Preheat oven to 160 degrees celsius (fan-forced).
Grease and line the base and sides of a 22cm springform pan with baking paper and set aside.
Cut the ends off the oranges and discard.
Chop the cooled oranges into pieces and place into the TM bowl.
Slowly increase to Speed 7 and continue to process until completely smooth (you'll need to scrape down the sides of the bowl occasionally).
Set aside in a separate bowl.
Clean and dry the TM bowl.
Add the eggs and caster sugar and mix on Speed 5 for 30 seconds.
Add the orange puree and mix on Speed 5 for 10 seconds.
Add the almond meal and baking powder and mix on Reverse, Speed 3 for 20 seconds.
Pour the mixture into the prepared baking tin.
Sprinkle the flaked almonds over the top of the cake.
Bake for 60 minutes or until a skewer inserted into the middle comes out with just a few crumbs on it.
Allow to cool completely in the tin (preferably place it into the fridge overnight.
Sprinkle with icing sugar just before serving.
To make the vanilla bean double cream, place the cream, vanilla bean paste and icing sugar into a bowl. Mix together until well combined.
Spoon into a serving dish. Sprinkle with grated orange zest and crushed pistachios.