Classic sauce Robert is a French brown onion and mustard sauce: onions cooked slowly in butter, reduced with white wine and a splash of vinegar, simmered in demi-glace or reduced brown stock, and finished off the heat with Dijon mustard and a pinch of sugar. It takes about 35 minutes, makes about 1 1/2 cups, and is the traditional sauce for pork chops and roast pork.
The sharp mustard and vinegar cut through fatty meat, which is why it is served with pork, goose and grilled sausages.
What Sauce Robert Tastes Like
Sauce Robert is savoury and tangy, with sweetness from the slow-cooked onions and a clear mustard kick. It belongs to the brown sauce family, so its body comes from demi-glace or a well-reduced stock. The mustard goes in last and off the heat, because boiling mustard turns it bitter and grainy. Add chopped cornichons to it and you have sauce charcutière, a close cousin.
Ingredients
- 2 tablespoons unsalted butter
- 1 medium onion, finely chopped (about 1 cup)
- 1/2 cup (120 ml) dry white wine
- 2 tablespoons white wine vinegar
- 1 cup (240 ml) demi-glace, or 2 cups beef or pork stock reduced to 1 cup
- 2 teaspoons cornstarch mixed with 1 tablespoon water (only if using stock)
- 1 1/2 tablespoons Dijon mustard
- 1/2 teaspoon sugar
- 1 tablespoon cold butter (optional, for gloss)
- Salt and black pepper
Instructions
- Cook the onion. Melt the butter in a saucepan over medium-low heat. Add the onion and cook gently for 10 to 12 minutes, stirring often, until very soft and pale gold. Do not let it brown hard.
- Reduce. Add the wine and vinegar, raise the heat and boil until reduced by two-thirds, 5 to 6 minutes.
- Simmer. Add the demi-glace or reduced stock and simmer gently for 10 minutes, skimming if needed. If using stock, stir in the cornstarch slurry and cook 1 minute more until the sauce coats a spoon.
- Finish off the heat. Take the pan off the heat. Whisk in the mustard and sugar, then the cold butter if using. Taste and season; it should be tangy but balanced. Do not boil again.
Cook and Prep Times
- Prep: 10 minutes
- Cook: 25 minutes
- Makes about 1 1/2 cups (serves 4 to 6)
Serving Sauce Robert With Pork
Season thick pork chops and sear them in a hot pan for 3 to 4 minutes per side, then finish in a 400°F oven until the center reaches 145°F, and rest them for 3 minutes. Pour off the fat, deglaze the pan with the wine and vinegar, and continue with the recipe from step 2 using the pork pan juices for extra flavour. The sauce is also good with roast pork loin, grilled sausages, pork tenderloin medallions and leftover roast meats reheated in the sauce.
Storage
Make the sauce up to step 3 and refrigerate it for up to 3 days, or freeze it for up to 3 months. Reheat gently and add the mustard and sugar just before serving.
Frequently Asked Questions
- Can I use whole-grain mustard? Yes, for a more rustic sauce; Dijon gives a smoother result.
- Why is my sauce bitter? The mustard boiled, or the onions burned. Add mustard off the heat and cook the onions gently.
- What is the difference between Robert and charcutière? Charcutière is sauce Robert with sliced cornichons stirred in at the end.
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