First heat the milk in a saucepan with half the sugar, when it comes to the boil add the rice, lower the heat and simmer gently for an hour, turning occasionally. When the rice has absorbed all the milk let it cool, keeping it aside. Now whip the eggs with the remaining sugar, grated orange zest and cinnamon. Then add to the creamed rice mixture, stirring from top to bottom. Now add the almond flour and the juice of one orange. Line the opening baking tray with baking paper and place the other orange on the bottom cut into slices.
Now pour in the mixture and bake in a well-heated oven at 180° for 50 minutes.
Let cool at least 4 hours before serving.