Vanilla and Hazelnut Tube Eclairs

Toast the hazelnuts in the oven for approximately 15 minutes at 150°C / 300°F. Once the hazelnuts are warm or cool, rub them between your hands to remove the skins. A little remaining skin is fine.

In a heavy-bottomed saucepan or cast-iron casserole dish, bring the water and sugar to a boil. At 116°C / 241°F, remove from the heat, pour the nuts into the liquid sugar and stir to coat them evenly. The mixture will turn white and sandy — this is normal.

Return to medium heat and stir continuously until the sugar melts again and caramelises (this takes around twenty minutes). It is essential to keep stirring to prevent the nut mixture from burning.

At the end of cooking, the nuts are nicely shiny and have taken on a lovely auburn colour. Spread them on baking paper and leave to cool.

Once everything is completely cold, break up the nut brittle and place it in a food processor with the fleur de sel.

Blend, taking regular breaks (to prevent the mixture from overheating), until you reach the consistency of a praline paste. The longer you blend, the more liquid it will become. You can choose to make an old-fashioned praline with some texture, or blend it until completely smooth.

Rehydrate the gelatine in water.

Break the white chocolate into pieces in a bowl (you can melt it slightly in a bain-marie or microwave).

Heat the 80 g (2.8 oz) of cream and bring to a boil.

Off the heat, add the rehydrated gelatin and stir.

Pour one-third of the cream over the white chocolate and stir with a spatula to create an emulsion. Then add a second third followed by a third, to obtain a smooth and well-combined mixture.

Add the 170 g (6 oz) of cold cream and the hazelnut praline, then mix again. Blend for a few seconds with a stick blender to ensure everything is well combined.

In a bowl, whisk together the egg yolks and sugar until the mixture turns pale and thick.

Add the cornstarch and mix.

Bring the milk to a boil in a large saucepan with the split and scraped vanilla pod. Pour a little of the hot milk in a thin stream into the bowl, whisking constantly, to temper the cream, then pour everything back into the saucepan with the remaining hot milk.

Whisk over medium heat until the cream thickens. Cook for 2 to 3 minutes.

Remove from the heat and add the butter cut into pieces. Whisk vigorously until the butter has melted, then transfer to a wide dish and cover with cling film touching the surface.

Refrigerate for at least 1 hour (you can make this the day before).

Once the pastry cream is well chilled, place it in a bowl and smooth it out with a whisk or electric mixer (or even in a stand mixer).

In a saucepan, combine the water, milk, salt, sugar and butter. Bring everything to a boil, then remove from the heat and add the flour all at once. Stir well with a wooden spoon.

Return to the heat for 30 seconds to dry out the panade (it should just slightly catch on the bottom of the pan).

Remove from the heat and transfer to a bowl. Leave to cool for a few minutes.

Beat the eggs then add them gradually to the dough. It should be neither too thick nor too runny, and should form a ribbon (if using an electric hand mixer, use the dough hooks rather than the whisk attachments; if using a stand mixer, use the flat beater).

Prepare the stainless steel tubes. Cut a Silpain mat to the dimensions of your tubes. I use tubes 3.5 cm (1.4 in) in diameter and 14 cm (5.5 in) long. The Silpain strip should line the inside of the ring perfectly.

Preheat your oven to 190°C / 375°F fan.

Stand the tubes upright on a perforated aluminium tray lined with a Silpain mat. I arrange them in groups of 3 in a triangle formation to space them evenly across the tray.

Pipe the choux pastry inside the tubes, filling them to one-third (with my tubes, I piped 70 g (2.5 oz) of choux pastry per tube).

Place a second Silpain mat over the tubes, add a second perforated tray, then weigh it down heavily (I used my cast-iron casserole dish). The choux pastry develops an incredible force during baking.

Place in the oven and bake for 1 hour 5 minutes.

At the end of baking, remove the tray from the oven, being careful not to burn yourself (I recommend removing the weights first). Carefully remove the choux pastry tubes, then peel away the Silpain strips. Leave the choux to cool on a wire rack.

File the bottom of the cylindrical choux with a microplane grater, just a little so it does not roll around on the plate.

Put the hazelnut praline into a piping bag with no tip.

Whip the hazelnut ganache in a stand mixer until firm enough to pipe but not so stiff that it splits. Transfer to a piping bag fitted with a fluted 14 mm nozzle.

Prepare everything you will need for the assembly — you should have 3 piping bags: the hazelnut praline, the vanilla pastry cream and the whipped hazelnut ganache.

Pierce the cylindrical choux with a knife by first making a small cross, then rotating the knife to create a small hole. For éclairs, I make 3 holes.

Fill the choux with the vanilla pastry cream (approximately halfway, even if it’s hard to gauge), then add a little hazelnut praline (bear in mind the more you add, the sweeter it will be) and finish with a little more vanilla pastry cream.

Turn the choux over (the 3 holes are no longer visible) and place on a serving dish.

Pipe the whipped hazelnut ganache on top, add some hazelnut praline, a few halved hazelnuts and a touch of gold leaf for decoration.

Refrigerate until ready to serve. If the process of making these cylindrical choux is still unclear, I recommend watching the videos I made and published on Instagram — click here and there.