Preheat oven to 350 degrees. Grease a 1/1/2 to 2 quart casserole dish.
Place the apples and 2 Tablespoons butter in a large skillet. Saute apples until tender. Place the sauteed apples in the bottom of the prepared casserole dish. Top with the cubed cinnamon raisin bread cubes.
Whisk the eggs in a medium bowl, until well blended. Add the flour,sugar,cinnamon,salt,vanilla and lemon zest to the eggs. Whisk until well blended. Whisk in the milk. Pour over bread cubes and apples.
Bake at 350 degrees for 45 to 55 minutes or until a knife inserted comes out clean. Let stand about 15 minutes, serve warm. Store any leftovers in the refrigerator.