Prep Pan & Bread: Grease a 9x13-inch ceramic or glass baking dish generously with softened butter. Arrange the cubed brioche bread evenly throughout the baking dish in a loose, uncompacted layer.

Whisk the Pumpkin Custard: In a large mixing bowl, vigorously whisk the eggs until smooth. Whisk in the whole milk, heavy cream, pumpkin puree, pure maple syrup, brown sugar, vanilla extract, pumpkin pie spice, cinnamon, and sea salt until completely emulsified and velvety.

Soak the Bread: Pour the custard slowly and evenly over all the brioche cubes, pressing down gently with a spatula to ensure every bread cube absorbs the spiced custard. (At this stage, you may cover with foil and refrigerate overnight, or let soak for 20 minutes before baking).

Make the Pecan Streusel: In a medium bowl, combine the flour, brown sugar, and cinnamon. Cut in the cold cubed butter using a pastry blender or your fingertips until crumbly pea-sized clusters form. Fold in the chopped pecans.

Bake to Golden Perfection: Preheat oven to 350°F (175°C). Scatter the pecan streusel evenly over the soaked casserole. Bake uncovered for 45 to 50 minutes until the center is puffed and set, the custard is fully cooked, and the streusel topping is deep golden brown and fragrant.

Rest & Serve: Let the casserole cool for 10 minutes before slicing into squares. Serve warm with softened salted butter, a generous drizzle of warm maple syrup, and fresh coffee.