Brown butter (aka “beurre noisette,” which translates to “hazelnut butter,” per Martha Stewart) is the product of gently cooking unsalted butter in a saucepan until it begins to foam and turn brown. The result is a nutty, savory, fragrant spread that (once it hardens back up a bit) can take your caramelized onions, pastries, or even your eggs to a new and oh-so-decadent level. Since butter is one of the main ingredients in hollandaise, incorporating brown into your sauce is as easy as blinking an eye.
But, be sure to add that warm brown butter into your whisked eggs and lemon juice carefully, says Food & Wine, just a little bit at a time. Otherwise, you run the risk of causing your sauce to separate; the heat could even curdle those tender egg yolks. To kick it up another notch, Food52 suggests adding both miso and brown butter to your hollandaise for extra umami flavor. Salty capers, pickled shallots, peppery arugula, and smoked salmon would all make fitting accouterments to your eggs benedict. If you want to make a big batch of brown butter ahead of time, says The Spruce Eats, it’ll keep in the fridge for a week or in the freezer for up to three months.