Prep: 11 minutes; Cook: 27 minutes.
Heat oil in a large skillet until hot; add onions. Sauté 10 minutes or until golden brown, stirring occasionally.
Add chili de arbol, bay leaves, and thyme; cook 1 minute. Add white wine, and cook until reduced by half.
Add fish stock. Bring mixture to a boil; cook 25 minutes or until liquid has almost evaporated. Add butter to pan, stirring until melted.
Small Bites, Big Nights (Clarkson Potter, 2007); Table 8, South Beach and New York