Preheat oven to 170°C. Grease a 20cm round cake pan and line base and side with baking paper.

Place oranges in a medium saucepan and cover with water. Cover with baking paper and a small plate to weigh the oranges down. Bring to the boil over medium-high heat. Boil for 1 hour or until very soft. Drain oranges. Set aside for 5 minutes to cool slightly. Roughly chop.

Transfer to a blender and blend until smooth (you will need 300g puree).

For the orange marmalade, peel rind from oranges, removing any white pith. Finely chop the peel and add to a saucepan of cold water. Place over medium heat and bring to a simmer, then drain and rinse peel under cold water.

Repeat process two more times. Segment peeled oranges over a bowl, squeezing any juice from the membrane. Place boiled peel, segments and juice, sugar and glucose syrup in a small saucepan over low heat. Cook, stirring regularly, until sugar dissolves. Bring to a simmer and cook gently for 30-35 minutes until mixture thickens and darkens (marmalade is ready when a small amount of mixture sets when spooned onto a cold plate). Remove from heat and set aside.

Meanwhile, mix eggs, orange puree and sugar in a bowl until smooth.

Combine almond meal, baking powder and bicarb in a separate bowl, then fold into orange mixture. Pour into prepared pan. Bake for 1 hour 10 minutes-1 hour 15 minutes until a skewer inserted in the centre comes out clean. Cool in pan for 10 minutes, then turn out onto a wire rack to cool completely.

To serve, top with some marmalade and whipped cream.