Monthly Archives: October 2026

How To Make French Onion Soup

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Illustration of whole and sliced onions

A Baxters Style Lower Salt French Onion Soup

A homemade soup inspired by the Baxters ingredient list – rich onion flavour, much less salt.

MakesAbout 800g (2 × 400g bowls)
Estimated salt~0.86g per 400g bowl
Baxters comparison2.16g salt per 400g tin

Ingredients

  • 250g brown or yellow onions, finely sliced
  • 2g Marmite or another yeast extract
  • 5g unsalted butter
  • 1.5g table salt
  • 10g sugar
  • ¼ tsp onion powder
  • 13.0g tomato puree
  • Small pinch white pepper
  • 14g cornflour
  • Small pinch dried parsley
  • 500ml water or unsalted vegetable stock
  • Tiny pinch celery seed or celery powder (optional)
  • 20ml cream sherry – caramelising stage
  • 10–12ml cream sherry – finishing
  • 0.5g MSG (optional, extra savoury depth without much extra sodium)

Method

1. Deeply caramelise one third of the onions. Melt the butter over low heat. Add about one third of the sliced onions and half the sugar. Cook slowly for 25–35 minutes until deep brown and jammy. Partway through, add 20ml cream sherry to deglaze the pan and deepen the colour. This is the main flavour building step.
2. Soften the remaining onions. Add the rest of the onions with a splash of water and cook until soft.
3. Build the soup. Stir in the tomato puree for 1–2 minutes. Add most of the water or unsalted stock, the remaining sugar, Marmite, onion powder, white pepper and optional celery seasoning. Simmer gently for 15–20 minutes.
4. Thicken. Mix the cornflour with a little cold water to make a smooth slurry. Stir into the soup and simmer for 2–3 minutes.
5. Finish. Stir in the remaining 10–12ml cream sherry, dried parsley and 1.5g salt. Add the optional MSG if using. Taste before adding any extra salt.
6. Standardise the batch. Add enough water to bring the finished soup to about 800g total weight. Divide into two 400g servings.

How the salt is reduced without losing flavour

Use onion browning for depth. Proper caramelisation provides sweetness, savouriness and roasted flavour that otherwise gets masked by extra salt.

Keep a little yeast extract. A small amount of Marmite gives the familiar savoury character while contributing only a modest amount of salt.

Use sherry, tomato and white pepper. These add acidity, sweetness, aroma and warmth, making the soup taste more seasoned without simply adding sodium.

Optional MSG. A tiny amount boosts savoury intensity, so the soup can taste fuller even at a much lower overall salt level.

Energy / serving~135 kcal
Protein2g
Fat3g
Carbs25g
per 400g serving · estimate

Salt Estimate: 1.5g added salt plus about 0.22g from 2g of regular Marmite equals about 1.72g salt per 800g batch, or about 0.86g per 400g bowl. This is roughly a 60% reduction compared with a 400g tin of Baxters French Onion Soup at 2.16g salt.

Tip: If the first taste seems slightly flat, add a little more sherry, white pepper, caramelised onion or the optional MSG before reaching for more salt.