In a heavy saucepan over medium-low heat, stir together the butter, heavy cream, and brown sugar; bring to a boil.
Reduce heat to low, simmer until the sauce thickens, for about 5 minutes. Pour over bread pudding to serve. Top with vanilla ice cream.
If you can, leave bread cubes out for a few hours so they get nice and dry. If not, just place them on a baking sheet and bake them at 350 for 10-15 minutes or until they’re dry but not toasted.
You can make this the night before and pop it in the oven for breakfast – it actually gets better if it sits overnight!