Sift the flour into a bowl. Add the softened butter in small pieces and mix with a spatula until incorporated. Form a well in the center, add 25 g caster sugar, 1 egg yolk, a pinch of salt, and 2 tablespoons water. Mix and knead for 2-3 minutes. Shape into a ball, wrap in cling film, and chill in the fridge for 30 minutes.
Roll out the dough to 4-5 mm thick and line a buttered porcelain pie dish. Prick the base with a fork and sprinkle with 2 tablespoons fine breadcrumbs.
Sort the blueberries quickly, avoiding washing to preserve their flavor. Arrange in a thick layer over the base. Bake at 190°C for 20 minutes. Meanwhile, whisk 100 g caster sugar, 2 eggs, and the crème fraîche.
Remove from the oven and pour the cream mixture evenly over the blueberries. Return to the oven and bake at 180°C for 15 more minutes. Dust with icing sugar when done and cool for 15 minutes before serving.
