Preheat oven to 180°C conventional or 160°C fan-forced. Line a baking tray with baking paper.
Combine melted butter and the egg in a mixing bowl. Whisk together until well combined. Add the cookie mix and the almonds to the wet ingredients. Mix well with a wooden spoon.
Wet hands and form the dough into 2 even logs. Place on the biscuit tray allowing room for the logs to spread. Flatten slightly. Bake to a light golden colour for 20 - 25 minutes. After removing from the oven, leave on the tray for 5 minutes, before moving to a wire rack to cool.
Reduce the oven temperature to 140°C.
Once cool, use a serrated knife to carefully slice the logs diagonally into slices about 1cm wide. Place the sliced biscotti back onto the oven tray and return to the oven for a further 10 minutes. Turn the biscotti over and return to the oven for a further 5 minutes or until dry and golden. After removing from the oven, leave on the tray for 5 minutes, before moving to a wire rack to cool.
When cool dip one side in melted dark chocolate and store in an air tight container.