1) Preheat the oven to 190C/Gas 5.
2) Place the flour, butter, and sour cream in a food processor and pulse to combine.
3) When the dough has formed a ball, pat with lightly floured hands into the bottom and sides of an ungreased 25cm tart pan with a removable bottom and 1cm sides, or a round au gratin dish.
4) Bake for about 18 mins, until the crust is set but not browned. Let cool while preparing the filling.
5) Lower the oven temperature to 180C/Gas 4.
For the filling:
1) Peel and thickly slice the apples. Arrange the apple slices in overlapping circles on top of the crust, until completely covered. Overfill the crust, as apples will shrink during cooking.
2) Combine the egg yolks, sour cream, sugar, and flour and beat until smooth. Pour the mixture over the apples. Place the tart pan on a baking sheet and bake for about 1 hr, until the custard sets and is pale golden in colour. Cover with an aluminium foil tent if the crust gets too dark. Transfer the tart pan to a wire rack to cool. When cool, remove the side wall of the pan.
3) To make the glaze, combine the preserves or jam and orange juice. Spread with a pastry brush over the top of the warm tart. Serve the tart warm, at room temperature or chilled. Garnish with fresh mint.