Soubise Sauce

Soubise sauce is a classical French onion sauce made by combining very tender, gently cooked onions with Béchamel sauce and cream, then blending the mixture until smooth. It belongs to the Béchamel family and is valued for its delicate sweetness, pale colour and velvety texture. The name is also used for dishes prepared with this onion-based sauce or purée.

How Soubise Sauce Is Made

The defining step is cooking the onions slowly without allowing them to brown. In this recipe, the onions are briefly blanched, drained and then cooked gently in butter until completely tender. They are combined with a smooth Béchamel and cream, then processed to create a refined sauce. A fine sieve can be used when an especially smooth finish is required.

Soubise Sauce Versus Béchamel

Béchamel is a white sauce made from a pale roux and milk. Soubise uses Béchamel as its base but adds cooked puréed onions and often cream. The onion component gives Soubise its characteristic sweetness and flavour, so it is not simply another name for Béchamel.

Uses in Classical Cuisine

Soubise can accompany eggs, poultry, pork and vegetables. It may be served as a sauce, used as a base for a vegetable gratin, or incorporated into a preparation for stuffed vegetables. Its mild onion flavour works particularly well with ingredients that benefit from a creamy, savoury accompaniment.

Chef’s Tips

• Cook the onions gently and keep them pale; browning changes the flavour and colour of the finished sauce.
• Drain the blanched onions well before sweating them in butter so excess water does not dilute the sauce.
• Whisk the Béchamel smoothly and cook the roux sufficiently before adding the milk.
• Blend the finished sauce thoroughly and strain it if a fine restaurant-style texture is required.
• Adjust the final consistency with a little milk or cream and season carefully with salt, white pepper and nutmeg.

Preparation Time: 10 minutes          Cooking Time: 35 minutes             Yield: 2 cups

Ingredients
2 cups sliced onions
2 tbsp butter
½ cup whipping cream
Béchamel Sauce:
1¼ tbsp butter
1½ tablespoons flour
1 cup cold milk
Salt, ground white pepper and pinch of nutmeg to taste

Preparation

Cook the onions: Place the sliced onions in a saucepan, cover with cold water, bring to a boil and simmer for  3 minutes. Drain through a sieve and refresh under cold water to stop cooking, place in a  sieve to drain the onions over a bowl.

Clean and dry the saucepan. Melt the butter on low heat, add the drained onions and cook covered on a gentle heat for about 20 minutes. Stir from time to time. Make sure that the onions do not develop any color and cook until totally tender.

Make Béchamel Sauce: Melt the butter in a saucepan. Mix in the flour using a whisk to create a smooth, loose paste. Whisk over moderate heat, allowing the butter and flour to cook for approximately 2 minutes without changing color from a buttery yellow. Add half of the milk, whisking vigorously to thoroughly blend. Then whisk more slowly over moderate heat, scraping the bottom and sides of the pan and add the remaining milk. Season it with salt, pepper and nutmeg. Bring to a boil for a few seconds and remove from the heat. The sauce should be thick enough to coat a spoon. If you are not using the Béchamel right away, you may add a knob of butter at the end, by melting it. This will prevent the formation of a skin that will eventually break and cause lumps.

Finish the sauce: Add Béchamel sauce to the cooked onions.  Add the cream and process with a hand blender, until smooth. Taste and rectify the seasoning of the sauce if necessary.

Use the sauce with Egg cocotte, hard boiled eggs, chicken, pork chops or stuffed vegetables.

Note: You may use the Soubise accordingly to a specific recipe or use it as follows:

• Stuff some large mushroom caps with some soubise sauce and roast them in a buttered dish at 400ºF for about 20 minutes or until golden. Serve hot.
• Blanch an equal amount of cauliflower and broccoli large florets for a total amount of 4 cups. Drain and refresh the florets. Place in a bowl, season lightly and toss with a soubise sauce (2 cups). Transfer the mixture into a buttered gratin dish and sprinkle over ½ cup of grated gruyere. Bake in a preheated oven at 400ºF for about 30 minutes or until golden brown. Serve hot.