Bring granulated sugar and water to a boil in a small saucepan, stirring until sugar dissolves. Remove from heat, and stir in Kirsch (or thin cherry preserves to a watery consistency in boiling water and then add to water and sugar). Let cool. Syrup will keep in an airtight container for up to 1 month. Combine the berries with 2 tablespoons of syrup in a large bowl. Set aside.
With the whisk attachment on a standing mixer, beat the cream. While whisking, add the sugar and vanilla. Beat on high speed until stiff peaks form. Place six wine glasses (or other festive glasses) on a work counter. Cut the cake into small pieces that will fit inside the glasses.
To build the parfaits, place a piece of cake in the bottom of a glass. Drizzle with syrup, top with 2 teaspoons of berries, and a generous dollop of whipped cream. Repeat with the remaining ingredients, layering cake, syrup, berries, and cream until the glasses are full. Chill until ready to serve.
