Estimated reading time: 6 minutes
This French white onion sauce is sweet, buttery, creamy and absolutely to die for.
Known in France as sauce soubise and made from store cupboard ingredients, this sauce is perfect with meats and vegetables and doesn't need cream to make it deliciously creamy.
So versatile, so make this sauce your own, with herbs or spices and you will love it!
What is special about this recipe
I have been eating this sauce ever since I can remember as it was always served with roast lamb. In fact, the sauce was not quite the same, as there was far less butter involved. The onions were boiled instead and the onion water was used for the gravy.
This version of sauce soubise is much richer, but still very easy to make. You don't need any difficult ingredients so you can make this at any time. Perfect for last minute entertaining, when you don't have time to go shopping.
Even better, you can make this sauce in advance and just reheat it!
What are the ingredients?
The base to the sauce is a basic béchamel, that just uses milk, butter, plain or all purpose flour and seasoning. Semi skimmed milk is fine to use, as the sauce gets the rice taste from the butter.
You will also need onions. I've used yellow onions, because they are a good all round onion and it's what I normally have to hand. I believe that other varieties would also work well but I wouldn't use red onions as I think the onion sauce would end up a pink colour!
How to make the sauce
There are two steps to making this. One part is the béchamel base and the other part is the onions.
You can make the béchamel in advance or make it while the onions are cooking, as it only takes about 10 minutes.
Peel and chop the onions. They don't don't need to be precisely cut as they will be blended later. If you prefer you can finely slice the onions or finely chop them, if you don't have a blender.
To make the white onion sauce, start by melting the butter in a medium sized saucepan.
Add the onions and stir them into the butter.
Put a lid on the saucepan and turn the heat to medium low for 20 minutes, stirring occasionally. The idea is to slowly poach the onions in the liquid until they are are really soft, not to colour and caramelise them.
Take off the lid and cook for another 10 minutes to allow some of the liquid to evaporate.
At this point you can use the onions as they are, blend them until they are completely smooth, or just pulse them a few times as I do.
This allows some of the onion really thicken and flavour the béchamel whilst also retaining the texture of the onions.
Now just add the onions and béchamel together and warm through when you are ready to serve.
Check the seasoning. I love to serve this with some freshly grated nutmeg.
In French soubise means a white sauce containing onions or onion purée.
This sauce is perfect with roast meats or chops. It can also be used on top of vegetables, sprinkled with cheese or breadcrumbs and then browned under the grill as a gratin.
Try it with roast leg of lamb, roast potatoes root vegetables and spicy French beans.
Although this sauce is delicious as it is, especially with lamb or pork , you can certainly add extra ingredients too.
Turn this into bread sauce by adding 100g of white breadcrumbs to serve with turkey.
Add some mustard or horseradish to serve with beef or steak.
Stir in some grated cheese to the hot sauce to serve with vegetables, then top with more cheese and brown under the grill.
This sauce will keep for 2 or 3 days in the fridge in a covered container.
To avoid a skin forming simply place some plastic wrap on the surface.
You can also freeze this sauce if you haven't mixed it with something else, like vegetables. After it has defrosted it will look like it has separated. Place it in a saucepan and warm it up slowly while stirring. In a few minutes it will return to its normal consistency.
Thick and luxuriant without having to add cream!
More French sauces to try
White Onion Sauce or Sauce Soubise
- 1 quantity béchamel sauce made with 500ml or 17fl oz milk
- 450 g onions
- 80 g butter
- seasoning to taste
- grated nutmeg optional
- Peel and chop the onions.
- Melt the butter in a medium sized saucepan, add the onions and stir them into the butter.
- Put a lid on the saucepan and turn the heat to medium low for 20 minutes, stirring occasionally.
- Take off the lid and cook for another 10 minutes to allow some of the liquid to evaporate.
- Add the onions to a blender and pulse them a few times to get to your preferred consistency.
- Add the béchamel to the onions and combine.
- Check the seasoning and serve.
Disclaimer: The nutritional information provided is approximate and is calculated using online tools. Information can vary depending on various factors, but we have endeavoured to be as accurate as possible.
Please refer to the post for detailed recipe instructions.