In a mixing bowl, combine the crushed digestive biscuits with melted butter. Mix until well combined, then press the mixture firmly into the bottom of a springform pan to form an even crust. Chill in the fridge for 15 minutes to set.
Dissolve gelatin in warm water and let it cool slightly.
In a large bowl, whisk together the Greek yogurt, heavy cream, powdered sugar, and vanilla extract until smooth and creamy. If using gelatin, gently fold it into the yogurt mixture.
Gently fold in half of the mixed berries into the yogurt mixture, reserving the rest for decoration.
Pour the yogurt and berry mixture onto the chilled biscuit crust, smoothing the top with a spatula.
Cover the torte with plastic wrap and let it set in the refrigerator for at least 4 hours, or overnight for best results.
Remove the torte from the springform pan, slice into wedges, and garnish with remaining berries and fresh mint leaves before serving.
