Mushroom and Fennel Bread Pudding

Melt the butter in a large frying pan over medium heat. When it foams, add the onion, season well with salt and pepper, and cook until soft, about 3 minutes.

Add the mushrooms, fennel, and celery; season well with salt and pepper; and cook, stirring occasionally, until softened and the mushroom juices have reduced, about 10 minutes.

Remove from the heat and let cool slightly in the pan, at least 10 minutes.

Heat the oven to 375°F and arrange a rack in the middle. Coat a 13-by-9-inch baking dish with butter and set aside.

Whisk together the cream, chicken broth, and eggs in a large bowl until smooth.

Add the bread, cooled vegetables, cheese, and herbs to the cream mixture and stir until the bread is well coated. Season well with salt and pepper, then turn into the prepared baking dish. Allow the bread to soak until well saturated, at least 15 minutes. Meanwhile, bring about 10 cups of water to a simmer over high heat in a large pot.Once the bread has soaked and the water is simmering, set the baking dish in a large roasting pan and add enough hot water to reach halfway up the sides of the dish.

Bake until the custard is set and the top is lightly browned, about 50 minutes.

Serve warm or at room temperature.