3 tablespoons cold, unsalted butter, cut into tiny pieces, plus extra for buttering the pan
1 large egg
1 teaspoon pure vanilla extract
Zest of 2 large lemons
2 tablespoons limoncello (lemon liqueur)
3/4 cup toasted pine nuts
Heat the oven to 350 degrees F. Butter a cookie sheet.
Place the flour, sugar, salt and baking powder in the bowl of a food processor
and pulse briefly to blend. Add the chopped butter and pulse briefly a few times,
just until the butter is broken down into very tiny bits.
In a small bowl, whisk together the egg, vanilla extract, lemon zest and limoncello.
Add this and the pine nuts to the food processor and pulse very briefly, just to
blend. The mixture should be moist but crumbly. Turn it out onto a flat surface
and press it together. Press the dough away from you using the palm of you hand
once or twice so everything is well moistened. Form the dough into a ball. Cut the
dough in half and roll each section into a 1-inch-thick rope. If the dough seems
too sticky, dust your hands with flour while rolling it. Place the two ropes on
the sheet pan a few inches apart. Flatten the tops slightly. Sprinkle lightly with
sugar and bake until very lightly golden, about 30 minutes. Remove from the oven
and let sit for about 5 minutes to cool slightly (if the logs are too hot when you
try to slice them, they can break).
When the two ropes are cool enough to remove from the sheet pan without breaking,
place them on a flat surface and cut into approximately 1/4 inch slices, cutting
on an angle using a quick, clean stroke with a sharp chef's knife (don't
try a sawing motion or you may cause the biscotti to break up). Place the cut biscotti,
cut side up, back on the sheet pan, and bake for about 10 minutes longer, or until
they are lightly browned.