Pistachio flour

Pistachio flour is made by grinding pistachio kernels into a fine meal. A common home method blanches the raw kernels briefly, dries them overnight, and then grinds them in a food processor, sifting the result and regrinding any large pieces. Lightly roasting the dried kernels first is an option for a deeper flavor.

The main thing to avoid is grinding too long, because the oils in the nuts quickly turn the meal into butter. Pulsing in short bursts keeps it powdery.

Bakers fold pistachio flour into cakes, financiers, shortbread, macarons and tart shells, usually along with ordinary flour. It gives a tender, moist crumb and a pale green tint.

For the best color, bakers choose plain, unsalted raw kernels, and they keep the finished flour in the refrigerator or freezer because the nut oils can turn stale.