Preheat oven to 350 degrees f (175 degrees C). Butter 9 x 13 pan or 1.5 qt casserole dish.
In a medium or large mixing bowl add sugar to blackberries, stir gently to coat berries. In another large mixing bowl combine the dry ingredients: flour, rolled oats, light brown sugar, cinnamon and nutmeg. Add butter and use a pastry cutter to cut the butter in until it reaches pea sized crumbles.
Add blackberry mix to baking dish, making an even layer that covers the bottom, then top the berries with the dry crumble crust mixture.
Bake in preheated oven at 350 degrees F (175 degrees C) for 40-45 minutes or until berries are bubbling around the edges and the topping is golden brown.
*This topping is very heavy, to reduce some of the calories use half the topping ingredients.