Add the strawberries to a bowl, sprinkle over the granulated sugar and strawberry liqueur and let steep 10 minutes.
Meanwhile, add the cream and powdered sugar to the bowl of a mixer and whip to soft peaks. Mash the strawberries with a fork and fold them into the cream.
Spoon the fool into individual glasses. Crush some ladyfingers on top. Top each with a sprig of mint and a whole strawberry!