The Secret 2-Ingredient Butter Sauce You Need to Know About

This past summer I had the opportunity to step behind the doors of a restaurant kitchen. This is a place I don’t venture often, but when I do get the chance to sneak inside, I am eager to grasp onto any little chef’s trick or tip I may come across in this uncharted territory.

And on this particular occasion, I hit gold. The chef was preparing baby potatoes for our dinner that evening. While I’d most likely roast them whole with olive oil and garlic, he instead dropped them into a pot of creamy, pale yellow liquid where they’d be poached. That liquid wasn’t broth or a funny-colored water: it was beurre monté.

Beurre monté is the French term for butter emulsified in water. An emulsion is when two ingredients that usually don’t mix, like oil and vinegar, are suspended together. Vinaigrette, mayonnaise, and hollandaise are all examples of emulsions. Butter itself is an emulsion. When butter is heated and begins to melt, this emulsion breaks — the butterfat naturally separates from the milk solids and water. But you can prevent this by whisking the cold butter into a little hot water while it melts, thus creating a melted emulsion of butter.

Read More: Food Science: What Is an Emulsion?

Start by heating a few tablespoons of water in a saucepan. When it reaches a simmer, reduce the heat to low, and slowly begin whisking in cubes of cold butter, just about a tablespoon at a time, until the water and melted butter have emulsified and formed a uniform, creamy, and thick sauce. Be sure to keep the heat low — if the sauce boils, it will separate. Use it immediately or keep it covered on the stove on low heat until you’re ready to use it.

Note: Any leftovers can be refrigerated, but you won’t be able to reuse it as beurre monté again, as the emulsion will break when you reheat it. Instead, use the leftovers to make clarified butter.

Perhaps the simplest and most delicious way to use beurre monté is as a finishing sauce. Drizzle it over steamed vegetables, broiled fish, pan-seared steak, or roasted chicken. Or ditch the cream sauce and use beurre monté in its place for the most decadent pasta or gnocchi.

You can also cook with it, just as I saw behind the scenes at the restaurant. Use it as a poaching liquid for potatoes, shrimp, or if you really want to get chefy, lobster. Whatever way you choose to use it is a good decision. Why? Because it’s warm, melted, extra-creamy butter — how could that not win?

Have you ever tired beurre monté? How do you like to use it?