Preheat oven to 375° F. Lightly grease a 2-quart baking dish. To prepare the topping: in a medium-sized bowl, combine oats, 1/4 cup of the flour, 1/4 cup of the sugar and the cinnamon.  Add butter; between fingers rub butter with dry ingredients to form coarse crumbs, stir in pecans.  In a large bowl, toss blueberries and apples with the remaining 1/4 cup sugar and 1/4 cup flour.  Pour blueberry-apple mixture into prepared baking dish.  Sprinkle the topping evenly over the fruit.  Bake until apples are tender and topping is golden, about 50 minutes.  Serve warm with vanilla ice cream or frozen yogurt, if desired.
*Alternatively, combine dry ingredients and butter in a food processor container. Pulse to form coarse crumbs.

Yield : 6 portions