Preheat oven to 350℉.
Generously butter a 9x13-inch baking dish to prevent sticking.
Cut the loaf of bread into 1-inch cubes and evenly spread them in the prepared baking dish.
Evenly sprinkle blueberries over bread cubes.
In a medium saucepan over low heat, combine the milk and butter, stirring until the butter is melted. Remove from heat and let it cool slightly.
In a large mixing bowl, whisk together the almond extract, cinnamon, granulated sugar, salt, and eggs. Slowly whisk the cooled milk mixture into the eggs until fully combined.
Pour the custard mixture evenly over the bread cubes, pressing down gently to ensure all the bread is soaked.
Bake in preheated oven for 45 minutes or until the top is golden brown and the custard is set.
Let the casserole cool for 5 minutes before serving. Enjoy warm with your favorite toppings like powdered sugar, maple syrup, or whipped cream.