Position knife blade in food processor bowl; add bread cubes. Process 30 seconds or until crumbs are fine. Sprinkle crumbs on an ungreased baking sheet; bake at 350° for 12 minutes or until browned. Set aside.
Combine mayonnaise and next 3 ingredients in a shallow bowl; stir well. Dip fish in mayonnaise mixture, and dredge in breadcrumbs. Place fish on a baking sheet coated with cooking spray. Bake at 425° for 22 to 25 minutes or until crispy and browned.
Quick, easy, and tasty. I used cod and panko crumbs.