Soubise is a creamy French onion sauce that combines one of the great mother sauces (bechamel) with lots of onions softened in butter.
This recipe takes around an hour to cook, but most of that time is spent waiting for the onions to soften, which is very hands-off cooking.
French White Onion Sauce
Bechamel is a mother "sauce", a bedrock of classical French cooking, and it's a recipe that many take for granted, but it is probably the one piece of classical cooking that I make the most!
It appears in everything from my classic baked lasagna bolognese to Welsh rarebit and my parsley sauce to cod mornay.
Bechamel also sits at the heart of this soubise recipe, a sauce that I think is woefully underused! It is a beautifully creamy and simple onion sauce that tastes sublime, and it's a crying shame that it is not more commonly known.
Dating back to the early 18th century and generally has changed little. It features gently stewed onions that are combined with a classic bechamel sauce.
It really is that simple, and it is one of "those" recipes that underpromise yet overdeliver!
The secret is in taking your time, it is all very easy, but you need to cook those onions on a very low heat, these onions should be stewed (sweat) down until soft with no hint of colour.
I blanch them in boiling water to give them a bit of a head start.
Then blend it with your bechamel and off you go, it's simplicity at its very best.
Frequently Asked Questions
CanI take a shortcut with the onions?
In short, no. I have added the only shortcut that really works, by blanching the onions a little. To be honest, the longer you can leave the onions, the better!
But you want to cook the onions very gently to keep the flavour, but without adding any colour. Cooking them this way is the very essence of this sauce.
Can I use low-fat milk?
Yes, there are no problems using low-fat milk in this recipe. However, given the butter, you really will not be saving a great deal on the fat front.
Do I have to pass the sauce through a sieve?
No, I like to do this to refine the sauce at the end, but it is not essential at all.
Can I make this in advance?
Kind of, yes. You will need to cover the sauce with cling film and make sure you keep it in contact with the sauce to prevent it from forming a skin.
If it does form a skin, scrape it off and discard it before reheating the sauce.
The sauce will thicken and will need to be let down with a little extra milk when it is reheated.
The sauce will be fine in the fridge for 2-3 days. I have read that it will be fine in the freezer, but I have been very disappointed with this sauce when it has been frozen.
Serving Suggestions
Soubise is a boldly flavoured sauce that works exceptionally well with red meats, with an equally large flavour profile.
In the photos on this page, I have served it with my marinated steak bavette (flank). In the video (below the recipe), I have served it with some simply grilled lamb chops.
It's fantastic with venison, whether it is roasted venison haunch or some quickly pan-fried venison steaks.
Likewise, it works wonderfully with wild boar steaks.
It's also a wonderful sauce with cured meats, like a nice gammon steak.
Equipment Used
I only name-check brands of equipment if I think that they make a material difference to a recipe. But if you have any questions, feel free to ask them in the comments section below the recipe.
- Hob/stovetop.
- 17/18cm or 7" saucepan.
- 15cm or 6" saucepan.
- 25cm or 10" frying pan with a lid.
- Blender.
- Fine mesh sieve (optional).
- Chopping board.
- Kitchen knife.
- Stirring spoons or a whisk.
- A combination of weighing scales, a measuring jug, measuring cups and spoons.
Soubise Recipe: A French White Onion Sauce
Ingredients
For the Onions:
- 1 Medium-Large Onion 175g
- 20 g Butter 1 tablespoon + 1 Tsp
For the Bechamel Sauce:
- 20 g Butter 1 tablespoon + 1 Tsp
- 20 g Flour 2 Tbsp
- 175 ml Full Fat Milk ¾ Cup
- ¼ teaspoon Salt
- 2 Pinches White Pepper
- 2 Pinches Nutmeg
Instructions
- Bring a 17cm or 7" saucepan of water to a boil.
- Cut the onions in half, peel them and then slice them into half-moon shapes, as finely as you can.
- Add the onions to the boiling water and blanch for 2 minutes, then drain and allow to steam dry for 2-3 minutes.
- Heat a 25cm or 10" frying pan over a low heat and add the butter for the onions. When the butter has melted, add the onions, partially cover with a lid and cook them for 30-35 minutes.You do not want to caramelise the onions; they should be cooked with no colour at all, so keep that temperature low and stir regularly.
- 5-10 minutes before the onions are ready, make your bechamel sauce.Melt the butter in a 15cm or 6" saucepan over medium heat, and when it has melted, add the flour, cooking for 3-4 minutes, stirring constantly.If the roux begins to colour, reduce the heat.
- Add the milk gradually to the pan until you have formed a smooth and uniform sauce.
- Remove the pan from the heat, and add the salt, white pepper and nutmeg to taste.
- Combine the onions and bechamel sauce, and transfer to a blender, and blitz until smooth. Adding milk until you have a texture that you desire.
- I like to pass the sauce through a fine mesh sieve before serving.