Bake for 20 minutes. Set aside, covered, for one day.
Preheat oven to 425ºF. Toss together first 4 ingredients in a large bowl; divide evenly between 2 rimmed baking sheets. Bake in preheated oven until golden brown, about 20 minutes. Reduce oven heat to 350°F.
Spread cornbread cubes evenly on a baking sheet; bake at 350°F until browned and crispy, about 15 minutes.
Drizzle butter mixture over toasted cornbread. Arrange Brussels sprouts in a serving dish; top with cornbread mixture and bacon.