Preheat oven to 180 C / Gas mark 4. Line a baking tray with baking parchment.
Combine the flour, sugar, ground almonds, baking powder and bicarbonate of soda. Combine the lemon zest, poppy seeds, egg, egg whites and lemon extract. Add the dry mixture and mix well. Form the dough into 2 logs.
Place logs onto the prepared baking tray. Bake in preheated oven for 30 minutes. Let cool slightly and cut diagonally into slices. Bake slices another 8 to 10 minutes until dry. Cool completely and store in an airtight container.
Altered ingredient amounts.
Because other reviewers said this wasn't lemony enough and because I didn't have any lemon extract, I added 4 tablespoons of lemon juice. I also added 1 T. of oil because I didn't want these to be rock hard. I also added extra poppy seeds. I can taste the lemon, and the biscotti are nice and crispy, without being tooth-chipping. - 21 Jul 2008
I have just made these for the first time and must say they are very tasty, I used only half the amount of sugar to help with the calories and they are still sweet and delicious
Would use more lemon next time for a real kick - 03 Oct 2012
Instead of the lemon extract, I used half a lemon juice that I had taken the zest off of. Then I had no problems getting the mixtures to bond together. They are yummy and really crispy. Ready to dunk into my coffee. - 04 Mar 2009