How to Make Black Butter. Black butter (OK, it's really dark brown) can make a nutty sauce, typically used on fish. This will make enough for two to three fish portions.
Heat butter in a heavy saucepan over medium heat until it is dark brown, with a nutty aroma. Swirl the pan occasionally so that the butter doesn't burn. (You don't want it actually black.)
Add vinegar and blend. Be careful, because the vinegar will cause the butter to hiss.
Try adding capers, parsley or both, after you've added the vinegar. To avoid dangerous spattering of vinegar on hot butter, pour the butter over the food, then deglaze the pan with vinegar and pour it over the food.