In a 9x13-inch dish, whisk together eggs, half & half, and vanilla.
Add bread slices, turning to coat.
Cover and refrigerate overnight.
Spray a separate 9x13-inch baking dish with cooking spray. Place blueberries in the bottom of the prepared baking dish. Lay soaked bread slices on top of the berries.
In a small bowl, use a fork to mix together sugar, butter, and cinnamon until crumbly. Sprinkle on top of bread.
Bake, uncovered, at 400 degrees F for approximately 30 minutes, or until bubbly and golden brown.