Finnish Blueberry Pie (Mustikkapiirakka) This is an authentic Finnish Recipe. Although it's called berry pie, it's actually more like cake. Mustikkapiirakka has a batter base, not a pastry crust & It's very delicious! Not to sweet, but has a fresh clean taste. This dessert is typically served as an afternoon treat, along with a scoop of ice cream, and a good strong cup of coffee. YUM!.