Step 1 Heat the oven to 350 degrees. Bring a pot of water to a simmer on the stove to use as a hot water bath.
Step 2 Whisk together the eggs and sugar in a bowl and set aside. Combine the cream and vanilla bean in a saucepan, and heat to a bare simmer. Remove from heat and pour a little of the cream into the egg mixture while whisking, to temper the eggs, then whisk the remaining cream until fully combined. Strain the mixture into a large bowl, discarding the vanilla pod.
Step 3Fold the bread cubes in with the custard base, and set aside for a few minutes to give the bread time to soak in the custard. When the bread is soaked and the mixture is cooled slightly, very gently fold in most of the chocolate chips. Spoon the mixture into a greased 2-quart baking or gratin dish, and sprinkle over the remaining chocolate chips. Place the baking dish in a roasting pan and fill the larger pan with the hot water to form a water bath.
Step 4Carefully place the roasting pan in the oven and bake until the bread pudding puffs and a toothpick inserted in the center comes out clean, 40 to 50 minutes. Serve warm.