Grease the bottom and sides of a 5 quart or larger slow cooker OR a 3.5 quart casserole slow cooker with butter or non-stick cooking spray to prevent sticking.
Add bread cubes, raisins and chocolate chips to the slow cooker.
In a medium mixing bowl, whisk together the eggs, milk, sugar, cocoa powder and vanilla extract until smooth and well combined.
Pour egg mixture over the bread mixture in the slow cooker and gently toss to ensure all bread is covered in the egg mixture.
Cover and cook on LOW for 2.5 to 3 hours.
Notes
If you are not a fan of raisins you can either omit them or substitute other dried fruit such as dried cherries, strawberries or cranberries. You can even add in a cup or two of fresh fruit.