Butter or spray large casserole baking dish and set aside. Cube brioche into 1/2 inch cubes.
In large food processor, combine ingredients for Cinnamon Pecan Crumble Topping. Pulse until combined and butter is cut into small pieces. Do not over-pulse, or else the butter will start melting and it will become dough-like.
Place half of the bread cubes into the casserole dish. Sprinkle half of the Cinnamon Pecan Crumble Topping. Repeat with remaining brioche cubes and crumble topping.
In a medium saucepan, heat the milk and granulated sugar until the milk is warm and sugar has dissolved. In a medium bowl, whisk together eggs, cinnamon, bourbon and maple syrup. Slowly pour in the warm milk mixture while constantly whisking.
Slowly pour liquid over bread cubes. If necessary, press down slightly so every piece of bread is coated. Cover with plastic wrap and refrigerate minimum 1 hour, up to 8 hours.
Heat oven to 350°F. Bake casserole 45-60 minutes, until the center is no longer soggy and the top is lightly brown. Serve warm with Bourbon Maple Syrup