Place first 5 ingredients in a bowl and gently mix to combine. Allow the berries to macerate with the mint and icing sugar 20 minutes. Whip the cream until very soft peaks form. Whip in the maple syrup and continuing whipping until stiff peaks form. Slice the cake into 8 portions. Serve each portion with a dollop of whipped cream and a generous spoon of berries. Garnish with mint and serve.
Options: If desired, use honey or icing sugar to sweeten the whipped cream instead of maple syrup. Substitute some of the fresh berries called for in this recipe with some of the other fresh berries available during the summer moths such as currants, gooseberries, and blackberries.