​1. Cut sourdough loaves into roughly 1 inch by 1 inch squares, place on baking sheet and allow to sit overnight or place in oven to make bread stale. Make bread is spread out to ensure contact with air.

2. Whisk together skim milk, cinnamon, nutmeg, all-spice, vanilla extract, pure maple syrup and eggs. Whisk mixture until thoroughly combined, pour evenly over stale sourdough bread. Cover and place into fridge overnight.

3. Slice granny smith apples (or other desired apples) into thin slices. Place butter into a pan, add apples and allow to become evenly coated in butter. Add cinnamon and brown sugar and continue to sauté just until apples give went tested with a sharp knife. 

4. For the streusel topping mix flour, brown sugar, cinnamon, nutmeg, allspice, and salt in a bowl. Add the cold butter cut into small cubes and mix until the mixture resembles fine pebbles.

5. Prepare a 9 x 13 inch baking pan by spraying it with non-stick oil. Layer the apple slices on the bottom of the pan, continue this until there are no remaining apples. Take the sourdough bread mixture out of the fridge and place over the apple layer, and then add the streusel topping over the top of the sourdough.

6. Preheat oven to 375 °F, place baking pan into the oven with a middle rack location. Bake for 1 hour and check for desired consistency (add or subtract 15 minutes from proposed bake time based on desired final texture). Let cool for 5 minutes, cut and serve with maple syrup.