Sauce Robert is a finished brown mustard sauce made with onions, mustard, and white wine simmered in a basic demi-glace. The French sauce is an ideal accompaniment for grilled pork and other meat dishes, but you may also enjoy it on roasted vegetables.
Sauce Robert is a compound sauce, meaning that it uses a mother sauce as one of its ingredients. You can use your own homemade demi-glace or save yourself a lot of work and buy demi-glace already made at a specialty grocer. Demi-glace itself starts with Espagnole sauce (brown sauce) as its mother sauce. The primary ingredient in Espagnole sauce is beef stock, which can take a lot of time to make from start to finish. If you have the time, making your own stock, brown sauce, and demi-glace can be very rewarding.
Sauce Robert rarely appears on restaurant menus today, and it seems many modern chefs aren't familiar with it or prefer to call the brown mustard sauce by a different name. It is still considered a classic savory sauce and has evolved little from its origins centuries ago. Make your own sauce Robert to see why it has stood the test of time.
In a small bowl, combine the sugar and lemon juice and stir until the sugar is dissolved.
In a heavy-bottomed saucepan, melt the butter and cook the onions over medium heat until soft and translucent. Don't let them turn brown.
Add the wine. Bring to a boil, then lower the heat a bit and continue simmering until the liquid has reduced by two-thirds.
Add the demi-glace, then lower heat to a simmer and reduce for about 10 minutes.
Strain through a mesh strainer. Add the mustard and the sugar-lemon mixture and mix well. Serve immediately.
For a twist on the traditional sauce, season your Robert sauce with:
- cracked peppercorns
- bay leaves (add after sautéing the onions and remove before serving)
- fresh thyme leaves
Origins of Sauce Robert
The sauce has origins at least as far back as the early 14th century, making it one of the oldest classic sauces. Sauce Robert is mentioned in a manuscript by Guillame Tirel (known as "Taillevant"). He was a master chef at French court who wrote "Le Viandier," one of the earliest recipe collections of the Middle Ages. The sauce later was ascribed to a 17th-century cook named Robert Vinot, which may be where it picked up its name. This version is closest to that which appears in Auguste Escoffier's "The Complete Guide to the Art of Modern Cookery" and in recent editions of "Larousse Gastronomique."