Difficulty: Easy. Preheat the oven to 200°C.
To make the pastry: Place the cake flour, icing sugar and salt in a mixing bowl. Rub the butter into the flour mixture using your fingertips. Make a well in the centre, add the egg yolks and mix using a fork. Slowly add the water and mix to form a soft dough. Place on a work surface and knead for a few minutes until smooth. Roll out the pastry to a thickness of 1 cm and use to line a 23 cm greased tart case. Fill with baking beans and bake blind for 10 minutes. Remove the baking beans and bake for a further 5 minutes. Reduce the oven's temperature to 160°C.
To make the filling: Mix all the ingredients using an electric beater until smooth – this will take about 5 minutes. Pour into the baked and cooled tart case. Bake for 30 minutes, or until the centre of the tart has a slight wobble. Remove from the oven and set aside to cool.
To make the citrus curd: Place the citrus juices, caster sugar and butter in a glass bowl over a gently simmering pot of water. Stir until the sugar has dissolved and the butter has melted. Add the eggs and egg yolks one at a time, whisking well between additions. Once all the eggs have been added, continue whisking in a figure of eight, until the curd feels heavy. Remove from the heat and set aside to cool, whisking every 5 minutes to prevent the curd from forming a skin. Once the tart and curd have cooled, top the tart with the curd and serve. Garnish with sliced ClemenGolds or naartjies.
