Peel the pears, remove the core, cut into 8 segments each and sprinkle with lemon juice. Melt the butter in the pan, add the sugar and stir for a minute. Add the pears and cook for about 8 minutes until they caramelize. Then transfer them in a round cake tin 26 cm in diameter.
Break the nuts and roughly chop the chocolate. Add the butter in cubes to the flour and mix with your fingertips until you get a crumbled mixture. Add brown sugar, oatmeal, milk and stir. Then add walnuts and chocolate.
Distribute the mixture over the pears and bake in the preheated oven at 180ºC for about forty minutes. Remove from the oven and serve.