Sprinkle sugar over the base of the prepared cake tin, cover with orange slices.
Beat the eggs with the sugar until frothy. Mix in the vanilla, butter and yoghurt. Combine the almonds, flour and baking powder, fold into the mixture. Spread the cake mixture on top of the orange slices.
Approx. 35 mins. in the centre of an oven preheated to 180°C. Remove and allow to cool a little. Remove the tin frame, tip out onto a cooling rack, remove the base, prick firmly with a wooden skewer.
To feed the cake
Combine the orange juice and icing sugar, pour over the cake, leave to cool.
Without adding any oil, toast the flaked almonds in a non-stick frying pan until golden brown. Scatter on top of the cake, dust with icing sugar.