Cut a thin slice off the top of each tomato. Scoop out pulp leaving a 1/2-in. shell (discard pulp or save for another use). Invert tomatoes onto paper towels to drain.
In a saucepan, place broccoli in a steamer basket over 1 in. of boiling water. Cover and steam for 5 minutes or until crisp-tender; set aside.
Brush inside of tomatoes with 2 tablespoons butter. Stuff broccoli into tomatoes. Toss bread crumbs and remaining butter; sprinkle over tops. Place in an ungreased baking dish. Bake, uncovered, at 425° for 15 minutes or until heated through.