Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.
Unfold the puff pastry on a lightly floured surface and cut into 12 equal squares.
Place the squares on the prepared baking sheet and bake for 15-20 minutes, or until golden brown and puffed up. Let cool completely.
In a bowl, whip the heavy cream with powdered sugar until stiff peaks form.
Gently fold in the raspberry jam.
To assemble the cookies, split each puff pastry square in half horizontally. Spread a layer of raspberry cream on one half, top with the other half, and repeat. Garnish with fresh raspberries.
Notes
For a richer flavor, add a teaspoon of vanilla extract to the whipped cream.