Preheat the oven to 190°C and heat a flat baking tray.
Process flour, butter, sugar, egg, and 15ml water until the pastry holds together.
Wrap the pastry in cling film and chill for 20 minutes.
Roll the pastry out and line a 28cm flan tin.
Prick the base with a fork and chill for 10 minutes.
Blind bake the pastry shell with weights for 15 minutes at 190°C.
Remove weights and bake for another 10 minutes until the base is cooked.
Cream butter and sugar, then blend in eggs, ground almonds, and almond extract.
Spread a thin layer of jam on the pastry and top with the almond mixture.
Bake the tart for 30 minutes until the filling is set.
Poach apricot halves in water until tender and allow to cool.
Arrange apricots on the tart and glaze with sieved, warm apricot jam.
Scatter toasted flaked almonds over the top before serving.