Place the cream, powdered sugar and vanilla in a large bowl and, using a hand mixer, whip until stiff.
Spoon one-third of the whipped cream mixture into a 10-inch round springform pan, smoothing evenly with a spatula. Top with half of the lemon cookies. Stir the raspberry preserves and disperse as evenly as possible over the cookies. Sprinkle over half of the raspberries, then top with another third of the whipped cream, followed by the remaining cookies. Stir the blueberry preserves and distribute as evenly as possible over the cookies. Sprinkle over half of the blueberries, then top with the remaining whipped cream and spread evenly. Garnish with the remaining fresh berries. Cover and refrigerate for 6 hours.
Run a paring knife around the springform pan and release the wall of the pan from around the cake, leaving the cake on the bottom of the pan. Transfer to a serving platter, top with the mint leaves and slice.