Put the ingredients for the dough together in a bowl and use the dough hooks to make streusel. Spread 2/3 of them in a 26-inch springform pan and press down on the bottom. Knead the remaining crumble and shape into a roll. Place the roll on the inside edge of the springform pan and press it down to a 2-3 cm high edge.
Put the pears in a colander to drain. Beat egg whites with salt until stiff. In a mixing bowl, whip the cream with the pudding cream into a cream in about 1 minute and carefully fold in the egg whites. Spread the cream on the crumble base and place the pears on the cream with the curvature facing up. Bake the tart for about 1 hour.
Let the cake cool for a good hour in the pan. Ideally on a cake rack so that the heat can escape.
For the chocolate icing, mix the cream with cocoa powder and cocoa powder in a saucepan, heat and allow to cool. Break the chocolate into large pieces and melt in the hot cream. Let cool a little and then pour evenly over the pears. Chill the tart for a good 3 hours before serving.