Heat oven to 190C/170C fan/gas 5.
Beat together the butter and sugar until it
is light and fluffy, about 1 min. Stir in the
almonds, egg and almond extract.
Stir in half the blueberries and spoon
into the pastry case. Smooth the top using
the back of a metal spoon, then scatter
over the remaining blueberries, pressing
them in lightly. Bake for 45-50 mins until
the pastry is crisp and golden, and the
filling is golden and feels firm to the touch.
Cool the tart for 10 mins in the tin,
then lift onto a serving plate. Dust with
a little icing sugar and serve warm or
at room temperature.