Cut bread in to cubes and place in a large bowl. In a medium bowl, whisk together the half & half, vanilla, eggs and sugar. Pour over cubed bread. Allow to stand at least 30 minutes and up to an hour, stirring a couple times while it stands.
Preheat oven to 350 F. Prepare ramekins by greasing and placing on a baking sheet (to catch any boil-overs).
Add cranberries and marmalade to bread/cream mixture and stir to combine. Using a slotted spoon, spoon bread in to ramekins. Extend the bread above the edge of the dish to create a crispy top.
Bake in pre-heated oven until a knife inserted comes out clean. (Check at the 30 minute mark.) Time will vary with size of ramekin.
Optional, prepare Butter Sauce by combining all ingredients except the vanilla in a small saucepan. Cook, stirring regularly, over medium heat until mixture comes to a boil, about 5 minutes. Stir in vanilla.