Melt butter, sugar, and syrup in a small saucepan over low heat. Bring to a boil and allow to boil for 1 minute (be careful not to burn).
Spray a 9 x 13-inch baking dish with cooking spray.
Pour melted butter mixture into the bottom of the pan. Sprinkle with half of the cranberries. Place the slices of bread on top.
In a medium bowl (or in a very large measuring cup) whisk together eggs, milk, creamer, vanilla, cinnamon, and nutmeg. Pour over the bread, sprinkle with remaining cranberries, cover with plastic wrap, and refrigerate overnight.*
In the morning, remove plastic wrap and bake at 350°F (180°C) for 30 minutes. Dust with powdered sugar and serve with syrup.
Notes
*If you don't have time to refrigerate overnight, that's fine. Just soak the bread in the custard for as long as possible (or at least 1-2 hours) before baking.