Combine heavy cream, half-and-half, and granulated sugar and set aside. Place chopped bread in buttered baking dish. Pour prepared liquid mixture over bread and let soak for 1 hour. Combine melted butter and brown sugar, set aside. Bake at 375°F, covered, in a water bath for 1 hour. After 30 minutes of baking, brush top with melted butter and brown sugar mixture. Continue baking for remaining 30 minutes.
Vanilla Butter Sauce
1 C white wine
1 C granulated sugar
1/2 vanilla bean
1/2 cup heavy cream
1 pound butter, unsalted, softened
In a small saucepan combine white wine, sugar, and vanilla bean. Simmer to half, add heavy cream and reduce by half again. Immediately beat in half the butter to form a creamy paste. Over low heat, continue beating in a piece of butter at a time just as the previous piece is almost fully incorporated. The sauce should have the consistency of a light hollandaise sauce.
Spoon warm bread pudding into 3-ounce serving cups and top with sauce.