In a bowl, cream the soft butter with a spatula. Add the icing sugar while continuing to work the butter.

Then add the egg, almond powder and vanilla and mix.

Finally, add the flour and salt. Mix gently without working the dough too much, you just want the flour to blend in.

Once you have a homogeneous dough, stop working at it. Shape it into a ball, flatten it slightly and wrap it in plastic film. Leave it in the fridge overnight.

First, poach the pears in a sugar syrup flavoured with tonka bean. To do so, heat 50 cl of water with the sugar in a saucepan. Whisk a little to dissolve the sugar. Bring to the boil.

Meanwhile, peel the pears, cut them in half and remove the core.

Once the water is boiling, add half a grated tonka bean (or a little less depending on the intensity you want), and place the halved pears. Lower the heat and cook for about ten minutes until the pears are soft.

Turn off the heat and leave the pears infused in the syrup for another 20 minutes.

You have two options here: either cut the pear halves into thin slices to garnish your cake, or make a compote. If you opt for the pear compote: cut the pear halves into small pieces. Place them in a saucepan with a tablespoon or two of tonka bean sugar syrup. Stew over a medium heat, stirring regularly, for about fifteen minutes.

Then give it a few blows with a blender (using an immersion blender). Finally, add the agar, bring to the boil for 2 minutes, while stirring, then turn off the heat. Let the compote cool and thicken. Your preparation is ready.

Put two salad bowls (preferably stainless steel) in the freezer (or refrigerator by default) for at least 15 minutes.

Heat 5cl of cream in a saucepan. Bring the cream to the boil, add the agar agar, stir for a minute, and continue boiling for another minute, then turn off the heat and leave to cool.

Take a bowl out of the freezer and beat the egg whites with a pinch of salt until stiff.

Once the cream + agar agar mixture has cooled (after about 10 minutes), mix it with the chestnut cream.

Take the second bowl out of the freezer and whip the cream with an electric hand whisk to turn it into whipped cream.

Gently add the whipped cream to the chestnut cream (as if you were mixing in egg whites).

Then very gently add the egg whites.

Set the mixture aside in the fridge for at least 2 hours.

Preheat your oven to 180°C.

Heat the hazelnuts for 5 minutes in a baking tray covered with baking paper.

Leave to cool for 2 / 3 minutes. Then, if you want to remove the skin (not necessary), you can put the hazelnuts in a cloth and rub them against each other (start this with the first third of the hazelnuts, take a second third and repete, and so on).

Put the sugar and water in a saucepan and heat to over 110°C (measure with a food thermometer).

In the meantime, crush the hazelnuts very roughly with a mortar and pestle.

Once the temperature of the sugar syrup has risen above 110°C, remove the pan from the heat and add the hazelnut pieces. Coat them well in the syrup.

Return the pan to the heat over a very low heat, keeping an eye on it, until the sugar has melted completely and caramelised. Add the butter and salt, let it melt, and turn off the heat.

Place a sheet of baking paper on a baking tray and pour in the hazelnut flakes. Leave to cool.

Cut out the base of the tart and place it on the bottom of your buttered or lined baking tin.

If the pastry starts to get a little sticky, put it back in the fridge for 2/3 minutes before making the edges.

Then make a ball with the dough scraps, and flatten again between two sheets of baking paper to make a long rectangle of dough that will allow you to cover the edges of the tin.

Gently seal the edges and bottom of the pie by pressing with your fingertips, then prick the pastry with a fork.

Preheat the oven to 160°C. Place a sheet of baking paper over the dough and cover the sheet with baking balls (or rice, or something else to put an even weight on the base).

Once the pastry has cooled, place the chestnut cream mousse on the base of the tart and smooth with a spatula to distribute the mousse evenly.

Then carefully pour in the pear compote (or the sliced poached pears).

Cover the pears with the caramelised hazelnuts and chill for 30 minutes before serving.) Enjoy!