01 - Preheat oven to 350°F. Grease a 9x9-inch baking dish with butter or non-stick spray.
02 - Arrange the croissant pieces evenly in the prepared dish. Sprinkle the chopped chocolate throughout, tucking some between layers to create rich chocolate pockets.
03 - In a large bowl, whisk together the milk, cream, eggs, sugar, vanilla extract, melted butter, and salt until smooth and well combined.
04 - Slowly pour the custard mixture evenly over the croissants and chocolate. Gently press down with a spatula to ensure all croissant pieces absorb the liquid.
05 - Let stand at room temperature for 10 minutes, allowing the croissants to fully soak up the custard.
06 - Bake in the center of the oven for 30 to 35 minutes, or until puffed and golden brown and the custard is set. A knife inserted in the center should come out clean.
07 - Cool for 5 minutes. Dust with powdered sugar before serving. Serve warm.