Caramelised onion sauce

The term 'caramelised' onion is often used, but few have the patience to see it through. The browning of onions is the result of two processes: the caramelisation of its own sugars and the browning of proteins (Maillard reaction). This doesn't happen in 5 minutes. The secret is slow cooking, which coaxes a deep, complex, sweet-savoury flavour profile from this simple vegetable.
🕒 Prep Time 10 mins
🍳 Cook Time 35 mins
Total Time 45 mins
🍽️ Servings 4 servings
🔥 Calories 190 kcal
🌍 Cuisine French, International

Ingredients

Equipment Needed

  • Wide frying pan: So the water from the onions evaporates quickly.
  • Wooden spoon: For continuous stirring.

Allergen Information

⚠️ Milk
⚠️ Sulphites

Instructions

1

Peel the onions, cut them in half, then into thin slices.

Tip: Try to cut slices of even thickness so they cook at the same time.
2

Melt the butter in the pan over a medium heat, toss in the onions, and salt immediately.

Tip: The salt helps draw water out of the onions, so browning can start sooner.
3

Reduce the heat to low. Sweat/fry the onions, stirring frequently, for about 20-25 minutes until they are dark golden brown and soft.

Tip: Don't rush it! If the heat is too high, the onions will burn before they soften and sweeten.
4

Sprinkle over the brown sugar and fry for another 1-2 minutes until shiny and sticky.

Tip: The extra sugar helps form the final caramel layer.
5

Pour in the white wine and scrape up the brown layer (fond) stuck to the bottom of the pan.

Tip: This is 'deglazing', where most of the flavour lies!
6

Cook until the wine has almost entirely evaporated.

Tip: This leaves only the aroma of the wine, while the alcohol burns off.
7

Remove from the heat (or turn to very low), stir in the sour cream and thyme leaves. Just warm it through, do not boil!

Tip: Sour cream proteins are heat-sensitive and will curdle if boiled.

Recipe FAQ

The onions caught on the bottom.
If they are black, start again, as they will be bitter. If just dark brown, pour in a little water and scrape it up.
The sour cream curdled.
You overheated it. Sour cream cannot withstand boiling. Just warm it through at the end.

Ingredients

  • 2 heads Red onions
  • 30 g Butter
  • 1 tbsp Brown sugar
  • 50 ml Dry white wine
  • 200 g Sour cream (full fat)
  • 1 tsp Fresh thyme (leaves)
  • 1 pinch Salt