Preheat the oven to 350?F.
Place the bread in a large bowl. In a small saucepan, melt 6 tablespoons butter and pour over the bread cubes. Use a rubber spatula to toss the bread and evenly distribute the butter. Grease a 9 x 13-inch casserole dish with the remaining tablespoon of butter and set aside.
Combine the heavy cream, milk, eggs, brown sugar, vanilla, cinnamon, nutmeg, salt, and raisins in a large bowl. Whisk to mix. Pour the cream mixture over the bread, and stir to combine. Allow the mixture to sit at room temperature for 30 to 45 minutes.
Transfer the bread mixture to the casserole dish and bake until the center of the bread pudding is set, 50 to 60 minutes.
Garnish the bread pudding with confectioners' sugar and serve warm with warm Whiskey Sauce.