Cook onions low and slow until caramelized, about 30 minutes. Add garlic and increase heat to medium. Cook 1-2 minutes until you can smell garlic. Add Worchestershire, broth, sherry and seasonings.
Place onion mixture in the bottom of an 8 x 8 casserole dish. Top with toast cubes. Sprinkle with cheese. Bake at 375 until hot, melted and golden, about 15-20 minutes if hot, 30-35 minutes if cool.
Keyword French onion soup, French Onion Soup bread, onion casserole, savory bread pudding