Pistachio Biscotti

The butter should be very soft so the mixture becomes especially smooth.

Mix only until combined so the dough stays tender.

Sifting reduces lumps and helps the dough mix more evenly.

For extra flavor, briefly toast the pistachios in a dry pan and let them cool.

The more uniform the log, the more evenly the biscotti will bake.

Well chilled, the dough will slice more cleanly later.

Prepare the sheets in advance so the slices can be placed on them immediately.

A large, straight-edged knife (not serrated) gives especially clean edges.

If the slices are very soft, chill them for another 10 minutes.

Watch the color toward the end, as browning can progress quickly depending on the oven.

On the rack the underside stays dry and the biscotti become crisper.

Dust just before serving so the powdered sugar stays nicely white.