Slow cooker onion soup is the lazy cook's dream - all the deep, caramelized flavor of traditional French onion soup without standing at the stove for an hour. Just load up your slow cooker in the morning and come home to pure comfort.
The magic happens over 8-10 hours on low heat. The onions slowly release their sugars and transform into a mahogany-colored, deeply sweet base. It's truly set-it-and-forget-it cooking at its finest.
Slow Cooker Benefits
- Hands-off: No stirring required
- Even cooking: Gentle, consistent heat
- Deep flavor: Long cooking = complex taste
- Easy cleanup: One pot cooking
Tips for Success
- Don't lift the lid - it releases heat
- Use low setting for best caramelization
- Add broth in last 30 minutes
- Season at the end
Serving Suggestions
- Crusty bread
- Melted cheese on top
- Fresh thyme
- Weeknight dinner hero
Slow Cooker Onion Soup
Hands-off soup with deeply caramelized onions.
Nutrition per serving
225Calories
6gProtein
24gCarbs
11gFat
3gFiber
14gSugar
Ingredients
Instructions
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Load slow cooker. Add sliced onions to slow cooker. Dot with butter. Sprinkle with sugar, salt, and pepper. Add thyme and bay leaves.
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Cook low and slow. Cover and cook on LOW for 8-10 hours (or HIGH for 4-5 hours), until onions are deeply caramelized and golden brown.
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Add liquids. Stir in sherry and broth. Cover and cook 30 more minutes on HIGH.
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Serve. Remove thyme and bay leaves. Season with salt and pepper. Serve as is or with cheese toast.
Recipe Notes
- Faster caramelization: Cook with lid cracked last 2 hours.
- Gratinée style: Add bread and cheese, broil in oven-safe bowls.
- Make-ahead: Keeps warming in slow cooker for 2 hours.
- Storage: Refrigerate 5 days. Freezes excellently 3 months.
