Preheat oven to 180°C/160°C fan-forced. Grease a 24cm (base) fluted ring pan. Place oranges in a saucepan. Cover with cold water. Bring to the boil. Drain. Return to saucepan. Cover with cold water. Bring to the boil. Drain. Set aside until cool enough to handle.

Roughly chop oranges. Remove and discard seeds. Process orange until smooth. Transfer to a bowl. Stir in butter, milk, eggs, flour, sugar and almond meal until combined. Pour mixture into prepared pan.

Bake for 50 to 60 minutes or until a skewer inserted in cake comes out clean. Stand cake in pan for 10 minutes. Turn onto a wire rack over a tray. Cool.

Make icing Place sugar, butter and orange juice in a heatproof bowl over a pan of simmering water. Stir for 5 minutes or until smooth. Set aside for 5 minutes or until slightly thickened. Pour over cake. Top with orange zest. Stand for 15 minutes or until set. Serve.

Preheat oven to 180°C. Brush a round 20cm (base measurement) cake pan with melted butter to lightly grease. Spread almonds over a baking tray. Cook in oven, stirring occasionally for 3 minutes or until toasted. Remove from oven and set aside.

Use an electric beater to beat together the butter and sugar in a large bowl until pale and creamy. Add the eggs 1 at a time, beating well between additions, until thick and creamy. Stir in half the flour, then half the buttermilk until just combined. Stir in the remaining flour and buttermilk along with the orange rind and orange juice until combined. Spoon into the prepared pan and smooth the surface. Bake in oven for 35 minutes or until a skewer inserted into the centre comes out clean. Remove from oven and set aside for 5 minutes before turning onto a wire rack for 30 minutes or until cooled. Place on a serving plate.

To make the icing, use an electric beater to beat together the sour cream and icing sugar in a medium bowl until combined.

Spread the icing over the cake and sprinkle with toasted almonds. Cut into wedges to serve.