Pre-heat your oven to 200°C. Using the tips of your fingers (or a food processor) rub the butter through the flour and castor sugar until the mixture resembles bread crumbs. Add the egg yolk and water and mix until it comes together as a dough. Knead for a minute or two. Wrap in cling film and refrigerate for 30 minutes.
Roll out (on a floured surface) and line a 23cm loose-bottomed tin with it. Refrigerate for a further 5 minutes. Prick the base with a fork, line the entire pastry case with tin foil, pour in baking beans (or uncooked rice) and bake blind for 10 minutes. Remove the tin foil and baking beans and bake for a further 12 minutes until the base of the tart is dry. (Much like a baby, a pastry case does not want a soggy bottom!) Remove and cool in the pan. Trim off any excess dough so you have a neat edge.
For the filling, beat the eggs. Fold them into the cream cheese, sour cream and castor sugar. Be gentle, do not whisk! Now add the boerejongens or raisins and ginger, pour into the tart case and bake for 30 minutes at 190°C. Lower the temperature to 150°C and bake cheese tart for a further 20-25 minutes until set and light brown.