Place the oranges in a saucepan and cover with water. Bring to the boil and then simmer for 1 hour until soft.
Pre-heat the oven to 150°C (fan oven)* and line and grease a 8 inch round x 4 inch deep cake tin.
Remove the oranges from the saucepan and cut in half to remove and discard the pips.
Place the oranges in a blender and blitz until smooth and set aside for a minute.
In a large bowl or food mixer beat the eggs and sugar together until pale and thick then mix in the pureed orange.
Add the polenta, ground almonds and baking powder and mix until thoroughly incorporated.
Finally stir in 250g of the chocolate chips (saving the extra 100g for the chocolate drizzle on top) until evenly dispersed.
Pour the batter in the prepared cake tin and bake for 10 minutes then turn the heat up to 160°C. Bake for a further 40 minutes until firm to the touch and an inserted toothpick comes out clean.
Once the cake is ready, remove from the oven and prepare the orange syrup by dissolving the honey in the orange juice in a saucepan on medium heat. Once dissolved and reduced slightly, prick the cake all over with a toothpick and brush the orange syrup evenly all over the surface of the cake.
Leave the cake to cool in the cake tin.
Once the cake has cooled and been removed from the cake tin then prepare the chocolate drizzle by melting the remaining 125g of chocolate chips in a bain marie or bowl set over a pan of simmering water. Pour the melted chocolate into a piping bag (or a small plastic food bag – just snip the corner off when you are ready to drizzle) and leave the chocolate to thicken slightly for about ten minutes before drizzling over the cake.