Melt the butter in a pan, then add the pears, rhubarb, sugar, cinnamon and cloves, and cook over a low heat for 10-12 minutes or until tender. Pour the mixture into a large dish.
Heat the oven to 200 degrees celsius or gas mark 6. To make the topping – tip all the ingredients into a food processor and pulse to crumbs. Sprinkle the topping over the fruit filling, then bake for 30 minutes or until golden brown on top.