Preheat your oven to 350 degrees F. Grease a 9-inch x 13-inch baking dish with nonstick cooking spray.
Heat a large skillet over medium-high heat. Add bacon to the hot skillet and cook until crispy, about 7 to 10 minutes. Remove to a paper towel-lined plate to drain.
In a large mixing bowl, beat together the eggs and milk.
Slice the bread into 1/2-inch cubes and place in the mixing bowl.
Core the apples and cut into bite-sized pieces. Add to the mixing bowl along with 3/4 of the bacon and raisins.
Mix everything together with a spoon, making sure all of the bread is coated in the egg mixture.
Pour into your prepared baking dish and spread out to fill the pan. Sprinkle the remaining bacon and raisins on top.
Bake for 40 minutes or until the casserole is set and golden brown on top. (If the casserole beings to brown too much, loosely cover with foil.)
Carefully remove from the oven and let stand for 5 minutes before cutting into 8 slices and serving warm.