Line a rimmed baking sheet with parchment paper.
In the bowl of an electric mixer, beat the butter, sugars and the zest of 1 and a half lemons on medium til light and fluffy. (Save zest of the other half for zesting over the icing).
With the mixer on low, add the eggs, lemon juice and vanilla and almond extracts.
Add the baking powder, salt and flour. Mix just until a dough forms. Avoid overmixing. Stir in the chopped almonds. If you find the dough too sticky to shape into logs, cover the bowl with plastic wrap and refrigerate dough for about 30 minutes to make it easier to shape. Turn dough out onto a lightly floured countertop. Flour your hands and knead the dough briefly to make it easier to work with.
Put half the dough onto your baking sheet lined with parchment paper. Lightly wet your hands and form into two rectangular shaped loaves about 11 or 12 by 2 inch each. Make sure to leave space between the two logs since they will spread when they bake.
Bake at 350 Fahrenheit 20-25 minutes til lightly browned. Remove from oven and allow logs to cool on the baking sheet for Allow to cool for around 20 minutes. Transfer logs to a cutting board and lightly spray the tops and sides with a water bottle. Spray one time per section. Wait 5 minutes before slicing.
Use a serrated knife to slice biscotti into 1/2 inch thick slices.
Reduce heat to 325 F. Lay biscotti on baking sheet cut side down and bake 20-25 minutes until cookies appear dry. Carefully turn cookies over once halfway through baking. Transfer cookies to a cooling rack and allow to cool completely.