Preheat the oven to 400°F (200°C).

Roll out the puff pastry sheets on a lightly floured surface until they are smooth and even.

Cut each sheet into circles that fit your baking sheet perfectly.

Place the pastry circles on the baking sheet, prick them with a fork to avoid puffing too much, and bake for 15-20 minutes or until golden and puffed.

Let the pastry circles cool completely on a wire rack.

In a saucepan over medium heat, combine the mixed berries and granulated sugar, cooking until the berries release their juicy goodness, approximately 5 minutes.

Dissolve the cornstarch in 2 tablespoons of water, then add this mixture to the berry mixture.

Stir and cook until it thickens, then remove from heat and let cool.

In a large bowl, use a mixer to beat the heavy whipping cream, powdered sugar, and vanilla extract until stiff peaks form, creating a fluffy whipped cream.

Place one pastry circle on a serving plate, generously spread half of the whipped cream evenly over the pastry.

Spoon the berry filling over the cream, ensuring it is spread evenly.

Add another luscious layer of whipped cream over the berry filling.

Top with the second pastry circle to create a beautiful layered effect.

Decorate the top with fresh blueberries and a light dusting of powdered sugar for an elegant finish.

Cut into slices and serve immediately.