Preheat the oven to 350 degrees F. Grease an 8x8 baking dish.
In a large bowl, whisk together the milk, eggs, sugar, and vanilla until well combined.
Place the cubed bread in the greased baking dish and top with the cranberries and walnuts.
Pour the milk mixture over the bread, being sure to pour over all sections of the dish. Let sit for 5 minutes.
Drizzle the melted butter on top and sprinkle the brown sugar on top.
Bake uncovered at 350 degrees F for approximately 40-45 minutes, or until the top pieces are golden brown, the filling is set, and the bread pudding springs back slightly when pressed.