Sift the flour with the salt. Rub in the butter until the mixture resembles crumbs.
Stir in the sugar into the flour and butter mixture, then add the egg yolk, egg and lemon zest.
Work everything together and refrigerate for 30-60 minutes.
Leave the dough out to warm up 20 minutes before rolling.
Roll the pastry 1/4 (3 mm) thick and line an 8 inch tart ring, pressing gently into the edge for a nice finish. Leaving it untrimmed, refrigerate for 20 minutes.
Pre-heat the oven to 400F. Press and finish the top edge of the pastry edge. Line the ring with parchment and pie weights or dried beans/rice and blind bake for 15 to 20 minutes.
Remove from the oven and lift the paper and pie weights from the tart.
Prepare the Filling
Reduce the oven temperature to 375F
Gently melt the sugar, butter and golden syrup in a saucepan. Remove from the heat and whisk in the beaten eggs. Add the lemon zest, fruits, walnuts and whisky or lemon juice. Mix well together and spoon into the tart shell.
Bake for 20-25 minutes. Remove from the oven and let cool.
Can be served warm or cold, with whipped cream, custard or ice cream.