2 cups milk
1 1/4 cups heavy cream
1 vanilla bean
5 oz. bittersweet chocolate, finely chopped
1/2 cup sugar
Pinch of salt
5 day-old croissants, cut into 1-inch pieces
4 oz. bittersweet chocolate, cut into 1/2-inch pieces
Caramel sauce for serving
Lightly sweetened whipped cream for serving
Preheat an oven to 325°F. Lightly butter a 2-quart oval au-gratin dish.
Pour the milk and cream into a heavy saucepan. Place the vanilla bean on a work surface. Using a small, sharp knife, cut the bean in half lengthwise. Using the knife tip, scrape the seeds from the bean, then add the seeds and bean halves to the milk mixture. Bring to a simmer over medium-high heat. Remove from the heat, cover and let stand for 30 minutes.
Return the saucepan to medium-high heat and bring to a simmer. Remove from the heat and whisk in the 5 oz. finely chopped chocolate until smooth.
In a heatproof bowl, whisk together the sugar, eggs and salt until blended. Form a kitchen towel into a ring and place the bowl on top to prevent it from moving. Gradually pour the hot chocolate mixture into the egg mixture, whisking constantly. Pour the mixture through a fine-mesh sieve set over a large bowl. Add the croissants and stir to combine. Let stand for 20 minutes, occasionally pressing the croissants into the custard.
Stir 3 oz. of the chopped chocolate into the croissant mixture and transfer to the prepared dish. Sprinkle the remaining chopped chocolate on top. Bake until a knife inserted near the center of the pudding comes out almost clean, 40 to 45 minutes. Serve warm or at room temperature. Accompany each serving with a drizzle of caramel sauce and a dollop of whipped cream. Serves 8.