Grease bottom and sides of 7 (10-ounce) custard cups with butter. Layer half each of bread cubes, turkey, broccoli, celery and Cheddar cheese in custard cups; repeat layers, ending with Cheddar cheese.
Whisk together eggs and next 7 ingredients in a large bowl; pour evenly over cheese, pressing down lightly to absorb liquid. Cover and chill 8 hours.
Bake, uncovered, at 350 degrees for 30 minutes or until golden. Let stand 10 minutes before serving.