Chocolate Praliné Marble Flan

One of the products that almost every French person cherishes is the Flan. It is essentially a type of custard made from milk or a combination of milk and cream, egg yolks, sugar, and thickening agents such as flour or cornflour. Flan can be baked with or without a crust. When it is accompanied by a crispy crust on the bottom and sides, it is known as Flan Pâtissier.

Originally, the flavor of flan is natural, typically with a hint of vanilla. However, like many classics, flan has also undergone modern interpretations, such as caramel flan, pistachio, coffee, and, of course, chocolate flan. Interestingly, flan takes on different forms in various countries—for instance, Pastel de Nata in Portugal and the English custard tart.

The texture of flan is very consistent, lacking the variety of textures found in other desserts, which can make it seem “flat” in terms of texture. However, not in this recipe! 🙂

Recently, I reunited with my friend, pastry chef Matthieu Carlin, whom you may already know from the best carrot cake recipe I shared on the blog. That recipe quickly became one of the most viewed posts.

Together, we crafted the star product of the newly opened pastry boutique at the Hôtel de Crillon—the Chocolate Praliné Marble Flan. This time, the flan consists of a puff pastry that is initially baked without the flan filling. It is then layered with hazelnut praliné, topped with a rich combination of vanilla and chocolate flan, resulting in a beautifully marbled appearance.

Certainly, you can make the flan with regular pastry dough instead of puff pastry, and you have the option of including or excluding the praliné layer. However, I highly recommend incorporating these two special ingredients. The puff pastry adds a unique texture to the flan, while the praliné layer provides a delightful twist that elevates it to another level.

Chocolate Praliné Marble Flan
ring mold 20 cm in diameter, 4.5 cm high

Ingredients
Flan crust:
Butter puff pastry (very cold, ready for work)

Praliné Layer:
200g praliné paste, recipe inside
10-15 hazelnuts, halved, roasted

Vanilla Custard Filling:
470g milk
1 vanilla bean split and seeded
105g egg yolks (5 L egg yolks approx)
85g sugar
40g cornstarch, sifted
65g butter, cubed
130g whipping cream

Chocolate Hazelnut Custard Filling:
170g milk
40g egg yolks (2 L egg yolks approx)
30g sugar
15g cornstarch, sifted
40g dark chocolate 60% chopped
35g hazelnut purée 
25g butter, cubed
45g whipping cream

Preparation
1. Flan crust: Place the ring on a baking sheet lined with parchment paper. Remove the puff pastry from the refrigerator and cut the base using the inside of the ring as a guide. Cut a 7 x 70 cm strip out of a sheet of puff pastry (or 2 shorter strips). Line the inner sides of the ring with the puff pastry strip(s) and fold the rest of the dough on the side of the ring outwards (as shown in the photo). Place the base in by gathering it up slightly so it doesn’t drag down the sides. Use the back of a teaspoon to press the base into the corners. Prick the puff pastry with a fork and refrigerate for 4 hours.
2. Preheat the oven to 175 degrees Celsius. Line parchment paper over the tart and fill it with sugar, dry beans, or pie weights. Bake for around 35 minutes.
3. Remove from the oven, carefully remove the weights and the parchment paper, and return to the oven for another 5 minutes until golden. Remove the baked crust from the oven, wait a few minutes, and gently trim the overhanging edges. Brush the crust with egg yolk and put it back in the oven for another 3-5 minutes of baking. Remove from the oven and allow it to cool to room temperature.
4. Praliné  layer: Spread a layer of praliné paste on the crust and dot with roasted hazelnuts.
5. Vanilla Custard Filling: In a medium saucepan, heat the milk and vanilla until simmering.
6. Meanwhile, in a large bowl, whisk the egg yolks and sugar together until they turn a creamy color. Add the cornstarch and mix well.
7. When the milk reaches boiling point, pour the hot liquid over the egg mixture. Do this a little bit at a time while mixing, so that you do not cook the eggs.
8. Return the mixture to the saucepan and bring it to a boil, stirring constantly so the eggs don’t scorch on the bottom.
9. When the mixture comes to a boil and thickens, remove it from the heat, add the butter and cream, and stir until combined into a smooth batter.
10. Transfer the batter to a pastry bag.
11. Chocolate Hazelnut Custard Filling: In a small saucepan, heat the milk until simmering.
12. Meanwhile, in a large bowl, whisk the egg yolks and sugar together until they turn a creamy color. Add the cornstarch and mix well.
13. When the milk reaches boiling point, pour the hot liquid over the egg mixture. Do this a little bit at a time while mixing, so that you do not cook the eggs.
14. Return the mixture to the saucepan and bring it to a boil, stirring constantly so the eggs don’t scorch on the bottom.
15. When the mixture comes to a boil and thickens, remove it from the heat. Add the chocolate, whisk until completely melted, and then add the hazelnut purée and mix.
16. Add the butter and cream, and stir until combined into a smooth batter.
17. Transfer the batter to a pastry bag.
18. Pipe alternating spirals from both mixtures over the praliné-covered crust. Swirl both batters together.
19. Bake at 170 degrees Celsius for 45-55 minutes (depending on the oven), until the filling is firm to the touch.
20. Remove from the oven, allow it to cool to room temperature, and refrigerate overnight.
*It’s recommended to remove it from the refrigerator about 15 minutes before serving.

Bon-Appétit
Sharon