Drain spinach; press between layers of paper towels to remove excess moisture.
Combine spinach, artichoke hearts, and next 5 ingredients in a bowl, stirring well. Spoon into a lightly greased 11" x 7" baking dish. Combine breadcrumbs and butter; sprinkle over spinach mixture.
Bake, uncovered, at 375° for 25 minutes. Serve with assorted crackers, bagel chips, or breadsticks.
Note: To get 1 1/2 cups French breadcrumbs, tear off a piece of a baguette. Pulse in a food processor until coarse crumbs form. Measure crumbs, tear off another chunk, and repeat procedure until you get 1 1/2 cups.