To make pastry, sift flour into a large bowl.
Using a pastry blender or 2 knives, cut in butter until evenly distributed and mixture resembles breadcrumbs.
With a fork, lightly mix in sugar, egg and enough ice water to make a dough.
Press into a ball and wrap in foil or plastic wrap.
Refrigerate 30 minutes.
To make filling, wash blueberries and dry on paper towels.
Put egg yolks and half the granulated sugar into a large bowl.
Beat until pale and creamy, 5 to 10 minutes with an electric mixer.
Mix in almonds.
Beat egg whites until stiff.
Beat in remaining granulated sugar; fold into egg yolk mixture.
Stir in blueberries.
Preheat oven to 375°F (190°C).
On a floured surface, roll out dough to fit an 8-inch (20-cm) flan tin with a removable bottom.
Place dough in tin without stretching.
Pierce bottom of pastry shell all over with a fork; spread evenly with filling.
Bake 40 minutes.
Cool 5 minutes in tin then transfer to a rack.
When completely cooled, sift powdered sugar over top.