Method:
1) Cook the oranges. Place the whole oranges (unpeeled) in a saucepan, cover with water and bring to the boil. Simmer for 45 minutes, or until very soft. Drain, cool slightly, then roughly cut and remove any seeds. Blend into a smooth paste.
2) Preheat the oven to 170°C fan forced. Grease and line a 20cm round cake tin with baking paper.
3) Make the batter. In a large bowl, whisk together eggs, sugar and vanilla until light and slightly frothy. Add the orange puree and mix to combine.
4) Add the dry ingredients. Fold in almond meal, BARLEYMAX flour, baking powder and salt until evenly incorporated. The batter will be thick and fragrant.
5) Bake. Pour into the prepared tin and smooth the top. Bake for 55-60 minutes, or until a skewer inserted in the centre of the cake comes out clean. Cover loosely with foil if the cake is browning too quickly whilst baking.
6) Glaze (optional). Warm the orange juice and marmalade together, then brush over the warm cake for a glossy finish.
7) Cool completely before serving. Serve as-is, or dust with icing sugar.