Preheat the over to 375 degrees. Line a backing sheet with tin foil that will be large enough to be able to end up covering the loaf of bread. Spray the foil with the non stick cooking spray.
Cut your loaf of bread into 1” strips going one direction, across the loaf, in a diagonal direction. Be careful NOT to cut all the way through. Turn the loaf and cut across your first set of cuts yielding 1” squares, still being careful not to cut all the way through. Place your cut loaf on the prepared baking sheet.
Melt two tablespoons of the butter. Then whisk together the butter, milk, and vanilla extract. Then stir in the sugar. Then whisk in the eggs, following with the cinnamon. Set aside. You may want to transfer it into a measuring cup to make it easier to pour over the bread
Take the remaining tablespoons of butter and thinly Slice as many pieces as you can and use them to stick in between the cuts. You don't have to fill each crevice but spread the butter pieces throughout the loaf of bread.
Slowly pour the mixture between all the cuts of bread. Do this slowly using your fingers to gently pull apart the pieces so the mixture will go all the way through.
Cover the bread with the foil. Put it into the oven for 20 minutes. After 20 minutes pull some of the foil down so the bread is exposed. Put back into the oven for 15 minutes more until all of the egg mixture is cooked.
Take the loaf out of the oven and drizzle the maple syrup on top. If you want to go the extra mile you can make cream cheese frosting and drizzle that as well!