French onion soup
Rich, deeply caramelised onion soup topped with toasted baguette and bubbling cheese — the ultimate cosy winter bowl.
This French onion soup is all about patience: slow-cooked onions turned to jammy, nutty gold give the broth its soul. Top with toasted baguette and a generous grating of vegetarian hard cheese for that molten, crunchy finish.
Make it on a blustery evening when you want something comforting but seriously grown-up — it feeds four and stores well if you need to make ahead.
Ingredients
- 1 kg brown onions
- 50 g unsalted butter
- 15 ml olive oil
- 5 ml caster sugar
- 2 garlic cloves — crushed or minced
- 30 ml plain flour
- 150 ml dry white wine
- 1.2 l vegetable stock — hot
- 2 bay leaves
- 4 sprigs fresh thyme
- 5 ml fine sea salt
- 5 ml black pepper — freshly ground
- 1 baguette — about 250 g; slice 1–1.5 cm thick
- 200 g vegetarian hard cheese — e.g. vegetarian Gruyère or mature vegetarian cheddar, grated
- 10 g fresh parsley — roughly chopped, to garnish
Equipment
- ovenproof soup bowls
- baking tray
- grater
Instructions
Peel the onions and slice them thinly from root to tip.
Heat the unsalted butter and olive oil in a large heavy-based frying pan over a medium–low hob. Add the sliced onions, caster sugar and half the fine sea salt. Cook gently, stirring every few minutes, until the onions are deeply golden and caramelised.
Add the garlic and cook for 1 minute until fragrant.
Sprinkle over the plain flour and stir well to coat the onions. Cook for 2 minutes to remove the raw flour taste.
Pour in the dry white wine to deglaze the pan, scraping any brown bits from the base. Allow the wine to reduce for about 3 minutes.
Add the hot vegetable stock, fresh thyme, bay leaves and the black pepper. Bring to a gentle simmer, then reduce the heat and simmer uncovered for 20 minutes.
While the soup simmers, slice the baguette and brush both sides lightly with olive oil. Arrange on a baking tray and grill until golden on both sides (about 4–6 minutes total, watching closely).
Remove and discard the bay leaves and the woody thyme stalks. Taste the soup and adjust the seasoning with the remaining fine sea salt if needed.
Preheat the grill to hot. Ladle the soup into ovenproof bowls, place a slice or two of toasted baguette on top of each bowl and pile generously with the grated vegetarian hard cheese. Put the bowls under the hot grill until the cheese has melted, bubbled and just begun to brown (about 3–5 minutes).
Scatter over the chopped fresh parsley and serve immediately while the cheese is molten.
Tips
- For even caramelisation slice the onions uniformly — a mandoline helps if you have one.
- If the onions are sticking, add a tablespoon of water rather than turning up the heat; that keeps the sugars from burning.
- Toast the baguette just before finishing under the grill so it stays crisp under the cheese but not sodden.
- Leftovers keep in the fridge for 2–3 days; reheat gently on the hob and refresh with a splash of stock if it thickens.
- If you don’t have ovenproof bowls, transfer to a preheated baking dish and grill, but divide into portions first for quicker heating.
Substitutions
dry white wine → dry sherry, same quantity (150 ml)
Stays closevegetable stock → beef stock, same quantity (1200 ml)
Noticeably differentvegetarian hard cheese → mature cheddar (200 g), grated
Stays close
Nutrition
Per serving · estimated
- 622
- Calories
- 20 g
- Protein
- 60 g
- Carbs
- 33 g
- Fat
- 6 g
- Fibre
- 11 g
- Sugar
- 1050 mg
- Sodium
FAQ
Can I speed up the caramelisation?
You can increase the heat but you risk burning and bitter flavours. A short cut is to use two-thirds onions and one-third red onion for deeper flavour, but proper low-and-slow cooking gives the best result.
Can I make this ahead?
Yes — make the soup up to 2 days ahead and cool. Reheat gently on the hob, toast the baguette and finish under the grill just before serving.
How do I make this gluten-free?
Use plain gluten-free flour in the same quantity and replace the baguette with gluten-free bread for toasting.
What if my cheese chars before melting?
Use the top shelf of the grill and watch constantly; if it chars too fast, move the bowls further from the element or finish briefly in a hot oven (200°C fan/220°C conventional) until melted.
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