In a bowl mix the flour, the butter, powdered sugar, baking powder and 2 tbsp water. Sprinkle half cinnamon and crushed with a fork, so as to obtain a crumbly shortbread. Pour into pre-greased with butter tray (20h15 cm) and pressed well. On the base tightly arrange the sliced ​​pears, such as overlapping with each other. Fruit sprinkled with chopped walnuts in large pieces. Cake pour previously beaten eggs, brown sugar, 1/2 tsp cinnamon and vanilla. Place in a preheated 200 ° C oven and bake 30-40 minutes. foreseen decoration fruit is cleaned and cut into thin slices. Heat sugar in a saucepan until caramelized and pour over it one at a fruit slices. Baked cake is cooled, cut into pieces and serve garnished with slices of caramelized fruit.