01 - Preheat the oven to 320°F. Line the base of a 9-inch springform pan with parchment paper.
02 - Crush the biscuits into fine crumbs. Mix with melted butter and sugar. Press firmly into the base of the pan. Bake for 10 minutes, then let cool.
03 - Beat the cream cheese and sugar until smooth. Add eggs one at a time, mixing gently. Blend in vanilla, sour cream, and flour until just combined. Pour over the cooled crust.
04 - Bake for 45–50 minutes, until the edges are set but the center is slightly wobbly. Turn off the oven, crack the door, and let cool for 1 hour. Remove and chill for at least 2 hours.
05 - Combine blueberries, sugar, and lemon juice in a saucepan. Cook over medium heat for 5–7 minutes, until berries burst. Purée, then strain to remove seeds.
06 - Sprinkle gelatin over water, let bloom for 5 minutes, then warm gently until dissolved. Stir into the warm blueberry purée. Let cool to room temperature.
07 - Whip the heavy cream to stiff peaks. Gently fold in the cooled blueberry mixture until smooth and airy. Spread evenly over the chilled cheesecake.
08 - Refrigerate for at least 2 more hours, or until set. Decorate with fresh blueberries and mint leaves before serving.