Preheat oven to 350 degrees F.
In a large bowl, mix together apples, 1/2 teaspoon pumpkin pie spice, 1/3 cup brown sugar, salt and tapioca starch, so dry ingredients coat the apples. Set aside.
In a food processor, pulse the torn bread until about 10 times. Then add pecans and pulse until all are uniform sandy crumbs. Toast in a dry skillet for about 5 minutes, until just fragrant. Do not overbrown. Remove from heat and stir in remaining 1 teaspoon pumpkin spice, 1/3 cup brown sugar, melted butter and generous pinch of salt.
In the bottom of a greased casserole pan, sprinkle 3/4 cup of the crumble. Then add apples, patting down lightly. Top with remaining crumble.
Bake for 45 minutes to 1 hour, putting aluminum foil lightly over the top 20 minutes into baking to avoid top becoming too brown. Serve warm with vanilla ice cream.