That sounds fancy, right? It's a way of describing how something the kids may never have eaten (fennel) is going to persuade them to love something they may never have liked (fish). Do you know fennel? The bulb is crisp and white, like a pale, overgrown celery bottom, and it smells yummily like licorice. It's delicious raw -- let your kids crunch on some while you're making dinner -- but caramelized until it's meltingly sweet? It's out of this world. Fish can be hard on the budget, but this dish is so packed with flavor that you can plan on small servings.
Heat the oven to 450ºF and prepare the fennel: trim the stems off the top of the bulb (save and chop some of the feathery fronds for garnish), then trim off the very bottom and slice the fennel thin, through its core in vertical slices.
Toss the fennel with the olive oil and 1/2 teaspoon salt, then spread it in a single, or very slightly overlapping, layer in a large baking dish. Cover with foil and roast for 15 minutes, then uncover it and roast for 15 more minutes.
Now flip the fennel slices, and sprinkle them with the balsamic vinegar and the juice from half the orange.
Arrange the fish fillets on top, season them with salt and pepper, dot them with the butter, and arrange the orange slices over them.
Bake the fish just until it flakes when poked with a fork, 10-15 minutes. Garnish with the chopped fennel fronds and serve over rice with some of the pan juices spooned over.