Slow Cooker French Onion Soup
Dive into a bowl of pure comfort with our Slow Cooker French Onion Soup, where caramelized onions meld beautifully with a savory broth. Crowned with a golden, cheesy bread topping, this dish is the ultimate cozy meal that’s easy to prepare and impossible to resist. Let your slow cooker work its magic while you savor the irresistible aroma wafting through your kitchen!
Prep
15
min
Cook
480
min
Serves
4
people
Level
beginner
📝 Ingredients
Serves 4🥬Fresh Produce(3)
- 2-3 garlic cloves
- 1 tsp Italian herbs (5 ml)
- 10-15 onions sliced (roughly 1.5kg)
🥩Meat & Seafood(1)
- 900ml of beef stock (30.4 fl oz)
🥛Dairy & Eggs(2)
- 100g butter (7 tbsp)
- 2 handfuls of cheese
🫙Pantry Staples(2)
- 6 slices of bread
- 2 tbsp brown sugar (30 ml)
🧂Spices & Seasonings(3)
- 1 bay leaf
- Salt and pepper
- Fresh thyme or any other herboptional
🍯Sauces & Condiments(2)
- 200ml white wine (6.76 fl oz)
- 1 tbsp Worcestershire sauce (15 ml)
👨🍳 Instructions
- 1
Slice all the onions up, you will cry.
- 2
Add all ingredients to the slow cooker except the stock, cheese, and bread, and cook for 8-10 hours on high. You can speed this up by softening them briefly in a pan.
- 3
Add in the stock, top with bread and cheese, then place under the grill for 8 minutes. Butter the bread too.
💡 Pro Tips
- ✓Slice onions 1/8-inch thick and uniformly so they break down at the same rate; uneven cuts cause some pieces to burn while others remain underdone during the 8-10 hour slow cook.technique1/8-inch thick
- ✓Toss the sliced onions with 1/2 teaspoon of baking soda before slow cooking to raise the pH and accelerate the Maillard reaction, deepening caramelization color and flavor without needing high heat.ingredient1/2 tsp baking soda
- ✓Add a splash of dry sherry or white wine (about 1/4 cup) in the final hour of slow cooking rather than at the start, since prolonged heat evaporates delicate esters that give the soup its aromatic acidity.timing1/4 cup, final hour
- ✓Broil the bread and cheese topping 4-5 inches from the heating element, not closer, so the gruyère melts and browns evenly over the full 8 minutes instead of scorching on top while staying cold underneath.equipment4-5 inches from broiler
- ✓Add the stock only after the onions are fully caramelized rather than cooking them together, since the water content in stock lowers the sugar concentration and prevents the Maillard browning reactions from occurring.techniqueadd stock last
Share this recipe
Prep
15
min
Cook
480
min
Serves
4
people
Level
beginner
Share this recipe
Slow Cooker French Onion Soup
Dive into a bowl of pure comfort with our Slow Cooker French Onion Soup, where caramelized onions meld beautifully with a savory broth. Crowned with a golden, cheesy bread topping, this dish is the ultimate cozy meal that’s easy to prepare and impossible to resist. Let your slow cooker work its magic while you savor the irresistible aroma wafting through your kitchen!
📝 Ingredients
Serves 4🥬Fresh Produce(3)
- 2-3 garlic cloves
- 1 tsp Italian herbs (5 ml)
- 10-15 onions sliced (roughly 1.5kg)
🥩Meat & Seafood(1)
- 900ml of beef stock (30.4 fl oz)
🥛Dairy & Eggs(2)
- 100g butter (7 tbsp)
- 2 handfuls of cheese
🫙Pantry Staples(2)
- 6 slices of bread
- 2 tbsp brown sugar (30 ml)
🧂Spices & Seasonings(3)
- 1 bay leaf
- Salt and pepper
- Fresh thyme or any other herboptional
🍯Sauces & Condiments(2)
- 200ml white wine (6.76 fl oz)
- 1 tbsp Worcestershire sauce (15 ml)
👨🍳 Instructions
- 1
Slice all the onions up, you will cry.
- 2
Add all ingredients to the slow cooker except the stock, cheese, and bread, and cook for 8-10 hours on high. You can speed this up by softening them briefly in a pan.
- 3
Add in the stock, top with bread and cheese, then place under the grill for 8 minutes. Butter the bread too.
💡 Pro Tips
- ✓Slice onions 1/8-inch thick and uniformly so they break down at the same rate; uneven cuts cause some pieces to burn while others remain underdone during the 8-10 hour slow cook.technique1/8-inch thick
- ✓Toss the sliced onions with 1/2 teaspoon of baking soda before slow cooking to raise the pH and accelerate the Maillard reaction, deepening caramelization color and flavor without needing high heat.ingredient1/2 tsp baking soda
- ✓Add a splash of dry sherry or white wine (about 1/4 cup) in the final hour of slow cooking rather than at the start, since prolonged heat evaporates delicate esters that give the soup its aromatic acidity.timing1/4 cup, final hour
- ✓Broil the bread and cheese topping 4-5 inches from the heating element, not closer, so the gruyère melts and browns evenly over the full 8 minutes instead of scorching on top while staying cold underneath.equipment4-5 inches from broiler
- ✓Add the stock only after the onions are fully caramelized rather than cooking them together, since the water content in stock lowers the sugar concentration and prevents the Maillard browning reactions from occurring.techniqueadd stock last