01 -
Line a baking tray with parchment. Mix flour, ground almonds, sugar and salt, then rub in cold butter until coarse crumbs form.
02 -
Set aside 60 g of the crumb mixture for the topping. Stir egg yolk and vanilla into the remaining mixture and press together into a soft dough.
03 -
Divide dough into 12 balls and flatten to discs about 6 cm wide on the tray. Make a shallow well in the middle of each, keeping a raised rim. Chill for 20 minutes.
04 -
Heat the oven to 180°C / 350°F. Toss blueberries with cornstarch and divide among the wells. Sprinkle the reserved crumble over the berries.
05 -
Bake for 18–20 minutes until edges are lightly golden and the berries have softened. Leave on the tray for ten minutes, then move carefully to a rack and cool for another ten minutes.
06 -
Keep cooled cookies in a sealed container in the refrigerator for up to three days. Serve at room temperature, or warm briefly in a low oven.