In a medium glass bowl microwave the chocolate at high power for 15 second intervals until melted, stirring between intervals.
In a medium saucepan over medium high heat bring the milk and cream to a simmer.
In a large bowl whisk the eggs, egg yolks, with 1/2 cup sugar, vanilla, and salt.
Slowly whisk the hot milk mixture into egg mixture, then whisk in the melted chocolate.
Spread challah cubes in prepared dish and pour the chocolate mixture over the top. Press bread into the custard until evenly soaked. Let stand 20 minutes.
Sprinkle remaining 2 Tbsp sugar over top. Set baking dish in a roasting pan and fill halfway with hot water. Bake the bread pudding about 50 minutes or until a knife inserted into center comes out clean. Remove dish from water bath and rest 20 minutes.
Bourbon Caramel Sauce: Heat 1 jar of Stonewall Kitchen Maple Honey Caramel Sauce. Add 2-4 tablespoons (or more!) of bourbon. Mix well. Bring to simmer stirring constantly, about 5 minutes. Drizzle over bread pudding and serve with whipped cream.