Cube the bread slices and divide between two bowls.
Beat together the eggs, milk and vanilla, pour 1/2 of the mixture over each bowl of bread cubes, stir and let the bowls sit and absorb the egg mixture while working on the next steps.
Over medium heat melt the butter then add the brown sugar and Karo syrup, stirring until hot- do not boil.
Spray a 9" deep dish pie plate with a non-stick spray and pour the butter/sugar mixture in and sprinkle the nuts evenly over top of the mixture.
Next, mix the granulated sugar, flour and cinnamon and toss with the sliced apples.
Pour one of the bowls of bread over the syrup and nuts, then layer the apples on top of the bread, then layer the remaining bowl of bread on top of the apples.
Sprinkle with nutmeg.
Cover and refrigerate over night.
Bake the next morning at 350 degrees, covered for 30 minutes, then uncover and bake for an additional 30 minutes.
Turn upside down on a serving plate and serve hot with warm syrup or, if preferred- sprinkle with powdered sugar.