Preheat oven to 180 C / Gas 4. Toast almonds in a shallow pan for 12 to 15 minutes, shaking the pan a few times, until almonds are lightly coloured. Set aside to cool.
Preheat oven to 190 C / Gas 5. Line 2 or 3 baking trays with foil, shiny side up.
In a large bowl, stir together the flour, bicarbonate of soda, baking powder, salt and sugar. Place 60g of these dry ingredients into the bowl of a food processor. Add about 60g of the toasted almonds and process for about 30 seconds.
Return mixture to the bowl of dry ingredients and stir in the remaining almonds and chocolate chips. In a large measuring jug, beat the eggs, vanilla and whisky with a fork to blend. Stir into the dry ingredients until moistened. Wet your hands and divide the dough into four portions. Keeping hands wet, form each quarter into strips about 23cm long, 5cm wide and 1.25cm high. Round the ends. Place two strips on each of the baking trays
Bake for 25 minutes in the preheated oven. If baking more that one tray at a time, reverse the trays top to bottom halfway through cooking time.
Using a metal fish slice remove the slabs from baking trays and let cool for 20 minutes on chopping board. Reduce oven temperature to 140 C / Gas 1.
With a serrated knife, carefully cut at an angle into slices about 1.25cm wide. Place the slices, cut side down, onto baking trays.
Bake 25 to 30 minutes in the preheated oven, until the biscotti is crispy and lightly toasted.
Turn oven off and open the oven door, allowing the biscotti to cool in the oven. When cool, store in an airtight container.