Prepare the Slow Cooker & Bread: Grease your 6-quart oval slow cooker thoroughly with butter or cooking spray. Cube the bread into 1-inch pieces and lay them evenly in the bottom of the slow cooker, slightly overlapping for better texture.

Make the Custard: In a large mixing bowl, whisk together the eggs, whole milk, maple syrup, vanilla extract, cinnamon, nutmeg, and salt until completely blended and slightly frothy.

Soak the Bread: Pour the egg and milk mixture evenly over the bread cubes in the slow cooker. Gently press the bread down to ensure every piece is submerged and absorbs the liquid. This initial soak is key to avoiding dry spots.

Add the Topping: In a small bowl, combine the brown sugar, cold butter pieces, and chopped pecans (if using). Sprinkle this mixture evenly over the top layer of the bread.

Refrigerate or Cook: For the best results, cover and refrigerate the assembled casserole for 4 to 8 hours, or ideally, overnight. This allows the custard to fully penetrate the bread, giving it that authentic bread pudding feel. If cooking immediately, allow at least 30 minutes of soaking time.

Cook in the Morning: Place the lid on the slow cooker. Cook on LOW for 3 to 4 hours or on HIGH for 1.5 to 2 hours. The casserole is done when the custard is set and the edges are golden brown. For a crisp top, transfer to an oven-safe dish and broil for 2-3 minutes, watching carefully until it achieves a perfect, golden crust.