Cut the bread into 1-inch cubes. Lightly grease a 9x13-inch casserole dish and add the bread cubes.
In a blender, combine silken tofu, coconut milk, cornstarch, sugar, vanilla, cinnamon, and salt. Blend until smooth.
Pour the custard over the bread cubes. Press the bread down into the custard using your hands until the bread is soaked. Cover and refrigerate for 8-12 hours, or bake immediately if preferred.
In the morning, preheat the oven to 350°F (175°C).
In a small bowl, mix brown sugar, flour, and cinnamon. Cut in the cold vegan butter using a fork or your fingers until the mixture resembles coarse crumbs. Sprinkle this topping over the casserole.
Bake uncovered for 40-50 minutes, until the top is golden brown and the casserole is cooked through.
Dust with powdered sugar and serve with warm, pure maple syrup.
