Prepare the Puff Pastry

1. Preheat the Oven – Set your oven to 400°F (200°C). Line a baking sheet with parchment paper.
2. Roll Out the Pastry – Lightly flour your surface and roll out the puff pastry to smooth out any creases.
3. Cut Out Hearts – Using a heart-shaped cookie cutter (or a sharp knife), cut out 6 hearts from the pastry.
4. Add Sugar and Egg Wash – Brush the tops of the pastry hearts with a beaten egg and sprinkle lightly with granulated sugar.
5. Bake – Arrange the pastry hearts on the prepared baking sheet and bake for 12-15 minutes, or until golden brown and puffed.
6. Cool Completely – Transfer the baked hearts to a wire rack and let them cool.

Make the Pastry Cream

1. Heat the Milk – In a medium saucepan, heat the milk over medium heat until just steaming. Do not boil.
2. Whisk the Yolks – In a separate bowl, whisk together the egg yolks, sugar, and cornstarch until smooth and pale.
3. Temper the Eggs – Slowly pour a little hot milk into the yolk mixture, whisking constantly to prevent scrambling.
4. Cook Until Thickened – Return the mixture to the saucepan and cook over medium heat, whisking constantly, until thickened (about 3-5 minutes).
5. Add Butter and Vanilla – Remove from heat and stir in butter and vanilla.
6. Chill – Transfer to a bowl, cover with plastic wrap (pressing it directly onto the surface), and refrigerate until completely cool.

Prepare the Raspberry Filling

1. Mash Raspberries – In a small bowl, mash half of the raspberries with a fork.
2. Mix with Preserves – Stir in the raspberry preserves and lemon juice until well combined.

Assemble the Napoleon

1. Split the Pastry Hearts – Carefully slice each heart in half horizontally, creating a top and bottom layer.
2. Layer with Pastry Cream – Spread a generous amount of pastry cream on the bottom half of each heart.
3. Add Raspberry Filling – Spoon a layer of raspberry filling over the pastry cream.
4. Top with Fresh Raspberries – Arrange a few whole raspberries on top of the filling.
5. Place the Top Layer – Gently place the top half of the pastry heart over the filling.
6. Dust with Powdered Sugar – Lightly dust the top with powdered sugar for an elegant finish.
7. Garnish – Add white chocolate shavings and mint leaves if desired.