Grease a 9x13x3” baking dish with the single tablespoon of softened butter.
Arrange the bread slices in the dish in two rows overlapping the slices.
In a large mixing bowl, beat eggs with a whisk.
Whisk in cream, half-and-half, granulated sugar and vanilla.
Carefully and evenly pour the egg mixture overtop of the bread.
Cover and refrigerate overnight.
The next morning: Remove dish from refrigerator and allow to sit out on counter 30 minutes before baking.
Preheat oven to 375°.
Place brown sugar, pecans, flour and salt in a small mixing bowl.
Grate the stick of cold butter over top of the pecan mixture.
Mix ingredients until crumbly.
Sprinkle pecan mixture over top of the bread in baking dish.
Bake, uncovered, about 50-60 minutes or until the custard from the eggs is completely set and topping is lightly browned.
Dust casserole with powdered sugar.
Drizzle maple syrup overtop of individual servings, as desired.