Preheat oven to 350°F (175°C). Grease a 13X9 inch baking dish and set aside.
On a cutting board, cut bread into 1-inch cubes.
Add bread cubes into prepared baking dish and sprinkle blueberries evenly across the top.
In a medium bowl whisk together eggs, milk, melted butter, cinnamon, vanilla, sugar and salt.
Pour the mixture evenly over the cubed bread and blueberries.
(If bake immediately) Bake for 35-40 minutes or until a knife inserted in the center comes out clean.
(If make ahead the night before) Bake for 40-50 minutes.
Remove from the oven set aside to cool for 5 minutes.
Dust with optional powdered sugar. Serve with ice cream and drizzle with caramel sauce!