Gather brioche bread, fresh blueberries, eggs, milk, sugar, and vanilla extract.
Cut the bread into cubes and let it sit to dry out slightly.
Whisk together eggs, milk, sugar, and vanilla to create a smooth custard.
Layer the bread and blueberries in a baking dish, pouring the custard over the top.
Allow the bread to soak in the custard for at least 30 minutes for optimal texture.
Bake at 350°F until the top is golden and the custard is set, about 45 minutes.
Serve warm with a dollop of whipped cream or a scoop of vanilla ice cream.