– Sift together the flour, baking powder and salt.– In a large bowl combine the lime zest and sugar. Add the flour mixture and pistachios, mix until combined.– In a small bowl whisk together the eggs, egg yolk, lime juice and vanilla until well blended. Pour the egg mixture over dry ingredients. Don't be afraid to get dirty and with you hands mix everything together. It will seem very dry at first but will come together and form a wet dough.– Scrape the dough onto the prepared baking sheet. Using wet hands, form the dough into a log about 14 inches by 3 inches. Rewet your hands if they get sticky again.
-Using a serrated knife and a sawing motion, cut the log on the diagonal into ½ inch thick slices.– Place the slices on the baking sheet, cut side down with a little bit of space between each slice. Bake for 15-18 minutes until the are dry.– Transfer the baking sheet back to the wire rack and let cool completely. – Melt the white chocolate in a bowl over a saucepan of simmering water, stirring occasionally.– When all of the chocolate is melted, using a spatula spread the white chocolate along one of the sliced sides of the biscotti then place face-down onto the parchment paper.