Prepare the crumb topping the day before the party. Prepare and bake the tomatoes an hour before; keep warm in a 200° oven.
Place ripe tomato slices in a single layer in a lightly greased aluminum foil-lined 15- x 10-inch jellyroll pan. Drizzle with honey, spreading honey into hollows.
Process bread in a food processor or blender until finely chopped.
Stir together breadcrumbs and next 3 ingredients; sprinkle evenly over tomato slices. Dot with butter.
Bake at 350° for 30 minutes or until tomato skins begin to wrinkle.
Broil 5 inches from heat 5 minutes or until tops are golden. Serve warm.