How Long to Cook French Onion Soup (Slow-Caramelized Onion Base) in the dutch oven
Specification: 3 lb yellow onions, halved and sliced pole-to-pole, softened then caramelized in butter, lid off
3-Step Execution Protocol
Preheat dutch oven to 300°F (149°C) surface — medium-low burner, butter foaming but not browning fast. Prepare french onion soup (slow-caramelized onion base) (3 lb yellow onions, halved and sliced pole-to-pole, softened then caramelized in butter, lid off).
Cook for 45–60 mins active caramelization (after a 10-min lid-on sweat). Do not flip; allow surface to develop undisturbed.
Onions have gone from straw-yellow through deep amber to the colour of dark whiskey, and the pot bottom is glazed with fond that lifts clean when deglazed. Rest for 0 minutes before serving.
No internal temperature target — caramelization is judged by colour, not by probe, so the field is omitted rather than guessed (HR-2). Timing reflects the Serious Eats/Kenji López-Alt method for genuine deep caramelization at medium-low without baking-soda or slow-cooker shortcuts.