From Sam Sifton, The New York Times.
You don’t need a recipe. Just take a stick of unsalted butter, and let it soften on the counter while you assemble the other ingredients: a tin of anchovies, some garlic cloves, a shake or two of smoked or regular paprika, a wee splash of lemon juice, and maybe, but probably not, some salt. Rinse and mince the little fish, mince the garlic, and fork everything together into the butter to taste.