Ingredients
Equipment
Method
Preparation
- Pre-heat the oven to 220C (200C fan). Peel & slice the onions, medium fine. See our onion Tip. Separate out the slices into a bowl.
- Add two generous knobs of butter and a good glug of olive oil to a hob-and-oven-safe casserole large enough to fit the onions & finished soup. Set over a medium heat until the butter melts. Add the onions, and stir to coat in the oil. Fry for a few minutes until they just start to soften with the heat medium. Then turn the heat down to low, and cook, stirring frequently, until the onions are soft, reduced and golden - at least 30 minutes and more like 45 minutes.
- While the onions are cooking, prepare the croutons. Slice the baguette quite thickly, allowing 2 to 3 slices per portion. Set on a baking tray and place into the hot oven for 30 minutes. About 15 minutes in, remove the croutons and sprinkle over a little olive oil. Rub the croutons in this and turn them over. Return to the oven for the rest of the cooking time, or until crisp & golden.
- While the onions & croutons are cooking, finish the preparation. Chop the parsley, medium. See our herb Tip. Remove the leaves from the thyme, and chop if needed. Grate both cheeses, enough to generously top the soup.
Making the soup
- When the onions are done, add the stock and white wine (if using). Stir and add a little boiled water if the soup looks too thick. Bring to the boil over a high heat. Add a splash of the cider vinegar, the thyme and 1 tablespoon of mustard. Season with pepper, but not with salt yet, and stir.
- When the soup is boiling, turn the heat down to low and cover with a lid. Simmer for one hour, stirring occasionally.
- When the hour is up, taste the soup and adjust with any of the flavourings until liked. Stir, and cook for another 15 minutes or so. Taste again, and season with salt & black pepper, if needed. Add the parsley, reserving some to garnish, and stir.
- You can now carry on to finish the French onion soup, or the soup itself can be kept, off the heat & covered, until you are ready to serve. Put in the fridge if keeping longer than a couple of hours. Also wrap or store the croutons in an air-tight container if making ahead.
Finishing & serving the soup
- Pre-heat the oven to 220C (200C fan). Bring the soup just up to the boil to warm it through.
- Top the soup with the croutons in one layer. Also top generously with the grated cheese. Place into the hot oven until the cheese is melted & bubbling slightly - 10 to 15 minutes.
- Serve immediately, making sure each portion gets croutons, and ladling over more soup.
- Garnish with more parsley, and enjoy!
Note: you can alternatively place the soup in bowls, top with the croutons and place under a grill (or in the oven). But only do this if you know your bowls are grill-safe (or oven-safe)! We don't use this method as we are not sure our bowls are - and also the casserole method is easier and less liable to spill.