Orange & Almond Dessert Cake

Preheat the oven to 350 degrees F. Butter a 9-inch springform cake pan and line with parchment or waxed (greaseproof) paper. Place the oranges in a saucepan, cover with boiling water and cook for 2 hours, topping up the water as it gets low. Alternatively, microwave the halved, unpeeled oranges for 15 minutes on high. The seeds may be removed by splitting the oranges. Place the cooked, unpeeled oranges in a food processor and process until smooth. Whisk the eggs in a large bowl. Add the sugar, ground almonds, and baking powder and stir to combine. Add the orange puree, then stir to combine thoroughly. Pour the mixture into the prepared cake pan. Bake for 1 - 1 1/4 hours, or until the cake feels firm to the touch and a skewer inserted in the middle comes out moist but not wet. Cool in the pan on a wire rack for at least 30 minutes before turning out. Serve dusted with confectioners' sugar or decorated with orange zest.