1-Prepare the bread: Slice the bread into 1-inch cubes and place them in a greased 9×13 inch baking pan. Arrange the cubes evenly to ensure uniform soaking.

2-Add the blueberries: Sprinkle the blueberries over the bread cubes, distributing them throughout the pan for consistent flavor in every bite.

3-Make the custard: In a large mixing bowl, whisk together the eggs, milk, cinnamon, brown sugar, and vanilla extract until fully combined and slightly frothy.

4-Pour the custard: Pour the egg mixture evenly over the bread cubes, ensuring all pieces get coated with the liquid.

5-Refrigerate: Cover the pan with aluminum foil or plastic wrap and refrigerate for 3 to 24 hours, preferably overnight. This allows the bread to absorb the custard fully.

6-Prepare the streusel: Just before baking, mix the brown sugar, flour, and cinnamon in a small bowl. Cut in the cold butter using a pastry cutter or fork until the mixture resembles coarse crumbs.

7-Add the topping: Sprinkle the streusel mixture evenly over the soaked bread cubes.

8-Bake: Bake uncovered at 350°F for 45 to 55 minutes until the top is golden brown and the center is set.