To make the berry topping, add mixed berries and water to food processor and puree until smooth.
Combine the 100 grams sugar and cornstarch in a medium saucepan. Stir in the berry puree.
Cook over medium heat, stirring constantly until mixture thickens and comes to a boil, about 8-10 minutes. Allow to boil for 1 minute, then remove from heat. Set aside and allow to cool completely.
To make the cheesecake, grease the bottom and sides of a 9 inch tin.
Combine the biscuit crumbs with sugar. Add melted butter and stir to coat. Press crumbs into an even layer in the bottom of the tin.
Mix cream cheese, sugar and 1 teaspoon of vanilla extract together in a mixer bowl until smooth and well combined.
In another mixer bowl, add the remaining 1 tsp vanilla extract, heavy whipping cream and icing sugar. Whip on high speed with the whisk attachment until stiff peaks form.
Gently fold about 1/3 of the whipped cream into the cream cheese mixture until combined, then add the remaining whipped cream and fold until fully incorporated.
Divide the mixture evenly between two bowls. Add 1/4 of the berry topping to one of the bowls and combine. Refrigerate remaining berry topping until later.
Spread the berry filling evenly into the crust and smooth the top. Gently add the vanilla cheesecake filling and smooth into an even layer.
Refrigerate for about 6-7 hours or until firm.
Remove the cheesecake from the tin, then spread remaining berry topping evenly on top. If needed, heat the berry topping up a bit so that it’s a more spreadable consistency. You don’t want it hot though, or it’ll soften the cheesecake.
Top the cheesecake with fresh fruit and refrigerate until ready to serve.