Place the orange in a saucepan of water, ensuring that is are covered. Bring to the boil and simmer for 1 hour. The orange should be soft enough for a fork to go through them.
Remove the orange and cool slightly.
Preheat the oven to 170C/325F degrees.
Place the orange into a food processor and blend into a paste with no lumps.
Add the almond flour, cocoa low carb sweetener, salt, baking powder and egg yolks.
Whisk the egg white into soft peaks and gently fold into the orange batter.
Place the batter into a greased spring form cake pan.
Bake for 1 hour until firm,
Eat and enjoy!