I'm a HUGE fan of "base recipes". Recipes that are easily adaptable to one's tastes, one's whims, and what's good at the farmer's market. This is one of those. Once you've mastered the basic formula, add whatever your little heart desires: fruit, chocolate, butterscotch, booze, nuts, herbs, spices, caramel, the sky is the limit. I've even reduced the sugar and made a rather rich savory dish for a holiday festivity. Cooking and baking should be an arena to play. This particular preparation has been heavily adapted from an old stand-by: Cook's Illustrated. —PieceOfLayerCake
Preheat the oven to 325F. Spread the brioche cubes out onto 2 sheet pans and bake in the oven until just SLIGHTLY toasted, about 15 - 20 minutes. Toss the cubes occasionally, and rotate the pans to ensure even toastage. Transfer the bread cubes into a large bowl and allow to cool completely. Generously butter/grease a 9 x 13" baking dish.
In another bowl, whisk together the brown sugar, egg yolks, vanilla and salt until combined. Pour over the toasted bread cubes and toss to coat. Allow to soak for 10 minutes, toss again, and allow to soak for an additional 10 minutes. Pour the mixture into the prepared baking dish. Sprinkle the raw sugar and flaked salt over the top of the pudding.
Bake the bread pudding for 45 - 50 minutes, or until the bread pudding is just set (It should jiggle as one mass with no visible liquid). Transfer the entire dish to a wire rack and cool completely before serving with various accouterments.