Preheat the oven to 180°C and grease a 20 cm springform cake pan with softened butter.
In a large bowl, add the egg yolks and sugar and use a hand beater to beat until the mixture is pale in colour and fluffy.
Gradually add the flour to the egg yolk mixture, followed by the Greek yoghurt, lemon zest, lemon juice and orange extract.
Using a clean bowl and beaters, whisk the egg whites until stiff peaks form. Fold the egg whites into the yoghurt mixture and pour the batter into the prepared cake pan.
Arrange the naartjie segments on top and bake for 50 minutes, or until the top of the cake starts to brown.
Remove from the oven and allow to cool in the cake pan completely before removing.
Dust with icing sugar once cool and serve with fresh whipped cream.
