Take the flavors of a coffee cake, apply them to a bread pudding, and you get this warming custard, reminiscent of French toast and perfect for brunch or dessert. For the best results, let the custard soak into the bread for at least 4 hours before baking.
Butter a 9x13-inch baking dish. In a medium bowl, whisk the milk with the eggs, vanilla, and 3/4 tsp. salt. In a mini chopper or food processor, pulse the walnuts with the brown sugar and cinnamon. Arrange half the bread slices in an even layer on the bottom of the dish; cut slices into small pieces to fill in the holes. Cover with half of the egg mixture, a third of the nuts, and a third of the maple syrup. Make another layer with the remaining bread and cover with the rest of the egg mixture, another third of the nuts, and a third of the maple syrup. Sprinkle with the rest of the nut mixture and maple syrup. Cover with plastic wrap, pressing down so the bread is completely submerged in the egg mixture, and refrigerate for at least 4 hours and up to 2 days before baking.
Position a rack in the center of the oven and heat the oven to 350°F. Let the bread pudding sit at room temperature while the oven heats. Bake until the custard starts to set, about 30 minutes. Loosely cover the pudding with foil to prevent browning, and cook for another 10 minutes. Let cool for 10 minutes and serve sprinkled with the confectioners’ sugar, if desired.
To make individual bread puddings, butter eight 10-oz. ramekins and fill each halfway with a layer of bread and cover with 1/8 cup of the egg mixture. Sprinkle with the nuts and 1 tsp. maple syrup. Repeat with a second layer of bread and egg mixture, nuts, and syrup; the ramekins should be about three-quarters full. Cover each ramekin with plastic wrap, pressing down so that the bread is submerged in the egg mixture, and refrigerate for at least 4 hours. When ready to bake, put the ramekins on a large rimmed baking sheet lined with parchment paper and bake in the center of a 350°F oven. Start checking for doneness after 30 minutes.