How to Make It
Preheat the oven to 325°. In a bowl, whisk the egg yolks with the granulated sugar and salt. In a heavy saucepan, combine the half-and-half, vanilla bean and cinnamon stick and cook over moderately high heat until bubbles appear around the edges. Gradually whisk the hot liquid into the yolks. Return the mixture to the saucepan and cook over low heat, stirring constantly with a wooden spoon, until the custard is thick enough to coat the back of the spoon, about 5 minutes; do not boil.
Spread the brioche crumbs in a baking pan and bake for about 5 minutes, or until lightly toasted. In a medium bowl, toss the crumbs with the brown sugar, melted butter and ground cinnamon.
In a shallow 2-quart baking dish, combine the bananas and blueberries. Strain the custard over the fruit. Sprinkle the crumb topping over all. Set the baking dish in a roasting pan and pour 1 inch of hot water into the pan. Bake the dessert for about 20 minutes, or until it is heated through and the topping is golden.