Pre-heat the oven to 180 °C. Toast almonds for 8-10 mins or until golden brown & fragrant. Allow them to cool & chop coarsely. Set aside.
Mix flax seed powder & warm water. Mix well & allow to stand for 5-10 mins.
Line a baking sheet with parchment paper or butter paper.
In a medium bowl, beat together flax seed egg & sugar till thick & fluffy on high speed. This should take about 5 mins.Add in vanilla extract & beat well.
In a separate bowl sieve flour, baking powder & salt. Whisk together.
Add flour mixture to flax seed mixture. Beat till combinedSlowly fold in the chopped almonds & chocolate.
Transfer the dough on the lined baking sheet & make a log of about 12" long & 3.5" wide. You might need to dampen your hands as dough would be sticky.
Bake for 25 mins at 180 °C or till firm to touch.
Remove from oven & cool on a wire rack for 10 mins.
Transfer to a chopping board & diagonally cut the dough into slices of 3/4″ thickness.
Reduce oven temp to 160 °F. Place the biscotti cut side down on the baking sheet & bake again for 12 mins. Turn over the slices & bake for another mins.
Remove from oven & cool on a wire rack.