Classic vanilla slice

A fantastic recipe for classic vanilla slice (Polish napoleonka), made using ready-made all-butter puff pastry. The secret to a truly exceptional napoleonka lies in perfectly baked, butter puff pastry and a silky vanilla cream prepared with milk, egg yolks, real vanilla and butter. Although the cream requires a little patience, the result is more than worth every minute spent in the kitchen. And honestly, I don’t know anyone who could resist a slice of this dessert… Be sure to serve it with fresh strawberries :).

Ingredients for the pastry:

• 2 sheets all-butter puff pastry (320 g each)

Prepare two large flat baking trays and line them with baking parchment. Place one sheet of puff pastry on each tray and allow them to come to room temperature. Prick the pastry all over with a fork.

Bake at 200°C for approximately 20–25 minutes, or until deep golden brown. As the pastry bakes, it will puff up. Pierce any large air pockets with a fork during baking to keep the pastry relatively flat. The pastry should be thoroughly baked, crisp and golden, but not excessively puffed. Remove from the oven and leave to cool completely.

Line a 20 x 30 cm baking tin with baking parchment. Trim the cooled pastry sheets to fit the tin, using a pizza cutter or serrated knife if necessary.

Ingredients for the vanilla custard cream:

• 1200 ml milk
• 9 large egg yolks
• 160 g caster sugar
• 90 g potato starch
• 2 teaspoons vanilla bean paste or seeds scraped from 1 vanilla pod (or 16 g vanillin sugar)
• 100 g butter, diced

All ingredients should be at room temperature.

In a large saucepan, bring the milk and vanilla seeds to the boil. As soon as it reaches boiling point, remove from the heat.

Place the egg yolks and sugar into the bowl of a stand mixer and whisk until pale and thick. Add the potato starch and continue whisking until a smooth paste forms. Gradually add 100 ml of the hot milk to the egg mixture, whisking continuously to temper it. Pour the tempered egg mixture into the remaining hot milk and whisk until combined. Return the saucepan to medium heat and bring to the boil, stirring frequently. Once the mixture starts boiling, continue cooking for approximately 2 minutes, stirring constantly, until the custard becomes thick and smooth. Remove from the heat. Add the diced butter and stir until completely melted and fully incorporated into the custard.

Assembly:

Place one baked pastry sheet into the prepared tin. Immediately pour the hot custard over the pastry base, spreading it evenly with a spatula. Cover with the second sheet of baked puff pastry. Leave to cool completely at room temperature, then refrigerate until thoroughly chilled. Chill overnight for the best texture and flavour.

The next day, remove the cake from the refrigerator. Dust generously with icing sugar and cut into portions using a sharp serrated knife. Decorate as desired, for example with fresh strawberries.

Enjoy!