Preheat the oven to 200℃ (180℃ fan)/400°F/gas mark 6. Place the flour in a mixing bowl and rub in the butter until the mixture resembles fine breadcrumbs. Stir in the icing sugar and orange zest. Add the egg yolk (keep the white you will need it later) and enough orange juice to mix to a dough.
Roll out the pastry on a well floured work surface and use to line a 23cm (9in) deep fluted flan tin. Lightly prick the base with a fork and chill for 10 minutes in the freezer.
Line with baking parchment and fill with baking beans. Bake blind on a baking sheet for 10 minutes, then remove the parchment and beans and bake for another 8-10 minutes until pale golden.
Meanwhile make the filling. Beat the butter and sugar together until very pale and fluffy, then beat in the whole egg. Beat well before adding the egg white and beat again. Fold in the almond extract, rosemary and the ground almonds.
Reduce the oven temperature to 180℃ (160℃ fan)/400°F/gas mark 4. Spread the jam carefully over the base of the pastry case. Then spoon in the almond filling and spread level in the case.
Arrange the blackberries over the surface of the tart and press down gently into the almond filling.
Bake for 45- 50 minutes until the filling is risen and golden. Allow to cool. Just before serving remove rom the tin and place on a serving dish, then lightly dust with a little icing sugar.
Freeze: for up to 2 months Defrost and bring to room temperature before serving.Nutrition information is approximate and is meant as a guideline only.