Melt the butter in a saucepan over low temperature, then let it cool.
Preheat the oven to 170°C.
In a large mixing bowl beat the eggs and sugar until creamy then stir in the vanilla extract.
Sift and fold in the flour then add the butter and the almonds and stir gently until combined.
Line a rectangular baking tray with parchment paper. Spoon the mixture into the tray, spread it out evenly.
Sprinkle the blueberries on the top, let them sink in the batter.
Bake for about half an hour until golden or until an inserted skewer in the middle comes out clean.
Turn off the oven, open the door and let the cake rest for five minutes. Then move it to a wire rack and let it cool.
When completely cooled, slice it into squares and sprinkle with icing sugar.