Preheat your oven to 350°F. Line a baking sheet with parchment paper.
In a small bowl, whisk together flour, salt and baking powder. Set aside.
In a medium-large bowl, add sugar and lemon zest. Rub the zest into the sugar in between your fingers for a few minutes. The sugar will begin to become yellow and fragrant.
Add softened butter and using a hand mixer mix together until well combined, about 2 minutes.
Add eggs 1 at a time, mixing each egg in well.
Add in vanilla and lemon emulsion and combine.
Add your dry ingredients to your wet ingredients and mix until just combined. Dough will be sticky.
Transfer your dough to the sheet pan and shape the dough into a flattened log shape that is about 12-13" long, 3-4" wide and about ¾" tall.
Place your baking sheet on the center rack of your oven and bake for about 30 minutes. The sides of your biscotti should be turning lightly golden and the top may be starting to show cracks.
Remove from oven and allow to cool for about 20 minutes.
Using a serrated bread knife, cut your biscotti at an angle, each piece about 1" wide.
Lay all the biscotti cut side down on the pan and place back in the oven for another 15 minutes. Halfway through baking, remove and flip all the biscotti over.
Remove biscotti from oven and transfer to a wire cooling rack.
In either a double boiler or in a heatproof bowl in the microwave, melt your white chocolate. The stovetop is a much better way as white chocolate is known to seize easily and the heat is more gentle and controllable in a double boiler.
After biscotti have cooled for about 20 minutes, drizzle or dunk biscotti in white chocolate. Allow white chocolate to cool and harden. Enjoy!
