1) Prepare the chips. Put it 1/2 glass of water and sugar in a low and wide saucepan, bring to a boil and simmer gently for 3-4 minutes. Meanwhile washed the pears and, with a mandolin, cut 8-10 slices of about 2 mm thick from the central part of each fruit. Transfer them in the sugar syrup, turn off the heat and leave them immersed for 1 minute. Drain them, align them on a baking tray lined with parchment paper and bake at 100 ° for 90-95 minutes.
2) Prepare the cocoa shortcrust pastry. Jumbled up flour with powdered sugar and cocoa. Add the yolk and then the cold butter into small pieces. Knead quickly with your fingertips until the mixture is crumbled. Form a ball, wrap it up in the film and transfer it to the fridge for 30 minutes.
3) You do the compote. Peel the pears, cut them into small pieces and transfer them to a non-stick pan with the lemon. Cook for 5 minutes; unite brown sugar and cook for 5 more minutes until you get a thick compote. Chop up the chocolate and melt it in a double boiler. With a kitchen brush, spread a 1.5 mm layer of melted chocolate on a sheet of baking paper; roll it up tightly and put it in the fridge to cool.
4) Roll out the pastry to 10 mm e coated a rectangular tart pan measuring 11x 35 cm. Prick the pasta, cover it with a sheet of baking paper and three handfuls of beans. Bake at 180 ° for about 15 minutes. Remove the beans and paper and continue cooking for another 15-20 minutes, until the pastry shell is cooked. Turn it out of the mold and let it cool on a serving dish.
5) Prepare panna cotta with coffee. Put soak the gelatin in cold water for 10 minutes. Reheat the cream with the sugar and when it is hot, dissolve the instant coffee and the squeezed gelatine. Jumbled up and let it cool. Stuff the pastry shell with the pear compote, leveling the surface well. Pour over the coffee panna cotta and transfer the tart to the fridge until the panna cotta has set.
6) Remove the tart from the fridge and garnish with the pear chips. Crush the cylinder of baking paper to break the internal layer of chocolate and obtain the flakes. Distribute them on the tart and serve.