Grate the zest of the lemon and dry it in the microwave for about 2 minutes, until it becomes a fine powder.
Peel the lemon down to the flesh, saving the pulp and discarding the seeds and membranes.
Bring the water to a boil and pour it into a blender jar along with the cold cubed butter and the lemon pulp.
Blend with an immersion blender until you have a smooth, even emulsion, then pass it through a fine sieve.
Cook the capellini in boiling salted water, then transfer them into the emulsion.
Toss gently until the sauce turns creamy and coats the pasta.
To serve, form a nest of capellini, nap it with the sauce, and finish with a generous dusting of the dried lemon powder.
Mirko Barrasso's (@barra_cucina) Capellini Burro e Limone. Saved from his Instagram reel and translated from the Italian. Just butter, lemon, and technique: a smooth lemon-butter emulsion tossed through delicate capellini and dusted with dried lemon zest. Quick, mild, and kid-friendly.
