Preheat the oven to 190°C / 375°F / Gas mark 5.
Lightly butter 6x10 cm loose-bottomed fluted tart tins.
Lightly dust a clean work surface with a little flour.
On a slightly floured surface, unroll the pastry arrange 5 tart tins on top, cut out the pastry a little larger than the tins then press into the tins and up the sides, trim the top of the pastry a little above the top of the tins.
Reroll trimmings and make the sixth tart case.
Prick the bases with a fork and chill for 15 minutes.
Line each of the tart cases with greaseproof paper and fill with baking beans.
Bake for 10 minutes, remove the paper and the beans then bake the empty tarts for 5-6 minutes further until just beginning to brown around the edges.
Remove from the oven and allow to cool.
Reduce the oven temperature to 180°C / 350°F / Gas mark 4.
To make the filling, beat the butter and sugar together until light and fluffy, gradually beat in the eggs then stir in the ground almonds and almond essence.
Spoon into the tart cases evenly and spread into an even layer.
Dot with 125g of blueberries.
Bake at for 20-25 minutes until golden.
Leave to cool for 20 minutes or until ready to serve.
Remove from the tart tins and top with the reserved blueberries.