For the chestnut-chocolate pear strudel, peel and quarter the pears, removing the core. Cut the pear quarters into thin slices. Coarsely chop the chocolate. Mix all ingredients for the filling.
Place a strudel sheet on a crockery hanger and brush with melted butter. Spread the chocolate-pear mixture evenly on one half of the dough and roll up the strudel with the help of the tea-hanger. Press the ends tightly. Place the strudel, seam side down, on a greased baking sheet and brush with melted butter. Combine the remaining ingredients to make strudels as well and place on the baking sheet. Bake the strudels in the preheated oven at 180 °C for about 15 minutes.
For the coffee sauce, heat the espresso with the sugar. Add the chopped chocolate and the cream and stir until the chocolate has melted. Finally, stir in the coffee liqueur.
Sprinkle the chestnut-chocolate-pear strudel with powdered sugar, cut into portions, place on dessert plates and pour the coffee sauce around.