In a large bowl, mix eggs, sugar, butter and cinnamon until combined.
Cut bread into one inch cubes.
Spray the bottom of a 9X13 baking dish with cooking spray.
Add layer of cube bread in the bottom of the dish. Then, add half of the blueberries. Repeat with another the rest of the cubed bread and blueberries.
Pour egg mixture evenly over top. Cover and let set for in fridge for at least 2 hours or overnight.
Bake for 45 minutes or until golden brown and cooked through. Allow to cool slightly. Serve with syrup and powdered sugar sprinkled on top if you'd like.
Notes
Cover leftovers and store in fridge for up to 3 days. Reheat in microwave or oven to 350 degrees F to desired temperature.