Preheat oven to 170°C. Grease and line the base of a heart-shaped pan.

Place the two whole oranges in a saucepan and cover with water. Bring to the boil and simmer, covered, for 1 hour, ensuring that the oranges remain covered with water. Drain and cool. Chop the oranges into quarters, discard any seeds, then place the chunks into a blender and puree until smooth.

Beat the eggs with the sugar until thick, then add the orange puree, ground almonds and baking powder and mix well.

Pour into prepared pan and bake for 1 hour. Leave the cake to firm up in the pan for 20 minutes then turn out, remove the baking paper and turn over to finish cooling right way up. This cake definitely mellows with a little time and can be prepared up to 48 hours in advance.

To serve, sift icing sugar on top and decorate with orange zest and almonds.