Ravioli with butter and sage, lemon zest and crushed pistachio

Time the sauce to the ravioli: for quick-cooking ravioli make the sauce first; for long-cooking ones start the ravioli first and the sauce partway through.

Bring a large pot of water to a boil with a generous spoon of sea or rock salt.

Add the frozen ravioli, stir quickly, and boil about 20 minutes, stirring now and then so they do not stick.

Grate the lemon zest.

Melt the butter in a pan over medium-low to low heat.

Add sage leaves, gradually adding more, without burning the butter or the sage; add more butter if it looks too little for the ravioli.

Cook the butter and sage gently over medium-low about five minutes, until the leaves are crunchy.

Lift the ravioli straight into the sauce and toss without breaking them so they absorb the butter; turn off the stove.

Add pecorino, a little crushed pistachio and lemon zest and toss again.

Variation: for the classic version, finish only with grated cheese, without lemon or pistachio.

Plate butter sauce and pecorino at the bottom, then the ravioli; decorate each with sage, more pecorino, lemon zest and crushed pistachio, and spoon butter sauce over.