How to Make It
Preheat the oven to 500°. In a 9-by-13-inch baking dish, toss the sliced fennel with 2 tablespoons of the oil, the anchovies and fennel seeds. Season with salt and pepper and spread the fennel in an even layer. Roast for about 15 minutes, stirring after 10, or until the fennel is tender and just beginning to brown.
In a small bowl, toss the bread cubes with the remaining 1 tablespoon of oil and season with salt and pepper. Set the halibut on the fennel and season with salt and pepper. Sprinkle the bread cubes over the fish and roast for about 8 minutes longer, or until the fish is cooked through and the croutons are golden and crisp. Sprinkle with the chopped fennel tops and serve.
Keep leftover bread in the freezer to have on hand for making croutons: Simply dice it and freeze it in a sturdy plastic bag or an airtight container. Since this recipe calls for baking the croutons with the fish only briefly, let the diced bread thaw before tossing it with oil. If you're making croutons for salad, however, there is no need to defrost the bread before baking.