Rinse fennel. Trim off stems, and reserve about 1 cup of the tender green leaves. Trim any bruises or dry looking areas from fennel. Cut each bulb in half from stem through root end.
Lay fennel bulb pieces in a 10 inch frying pan, and add broth. Cover, and bring to a boil on high heat. Simmer until fennel is tender when pierced, 20 to 25 minutes. Transfer fennel to a shallow casserole, 9 to 10 inched wide; lay cut side up.
Boil broth, uncovered, on high heat until reduced to about 1/2 cup. Stir in about half the fennel leaves. Spoon mixture evenly over fennel.
Mash cheese with bread crumbs. Dot mixture evenly over fennel. If making ahead, cover and chill up to 1 day. Also wrap remaining fennel leaves in a towel, seal in a plastic bag, and chill.
Bake casserole, uncovered, at 375 degrees F (190 degrees C) until cheese begins to brown and fennel is hot, about 20 minutes. Tuck remaining leaves around fennel. Season to taste with salt.