Rinse the oranges and place them in a pot. Cover with water and simmer on low heat for 1 hour.
After 1 hour drain the pot and place the oranges in a blender. Blend for approximately 1 minutes until the oranges have formed a puree
To make the ground pistachios place them in a coffee grinder or food processor and grind until there are no chunky pieces and everything has ground down to a fine powder.
Preheat oven to 175 degrees celsius (350 degrees Fahrenheit). Grease a loose bottom cake pan
In a bowl combine the orange puree, eggs, honey, ground pistachios, almond flour, vanilla extract and baking soda. Pour into the greased cake pan
Bake for 1 hour. If the top begins to brown too quickly, cover with tinfoil. The cake will be done once a cake inserted into the top comes out clean.
While the cake is baking, in a small pot combine 1/2 cup orange juice with 2 tbsp honey and allow to reach boiling point before reducing the heat to simmer. Allow to simmer until the amount of liquid has reduced by approximately half. Remove from the heat and set aside until the cake has come out of the oven.
Once the cake is out of the oven, brush the orange and honey mixture over the entire surface. Top with the slices of dried orange. Run a knife around the edges of the pan to loosen before unclasping the outer ring.
*If making the dried orange slices from scratch, wash an orange and using a sharp knife thinly cut it into slices no thicker then 0.5cm. Place the slices on a parchment paper lined baking sheet and bake for one hour at 150 degrees Celsius, flipping half way through baking to ensure they don't burn