Preheat the oven to 180°C (356°F).
Roughly chop the nuts.
In a bowl, mix together the whole wheat flour, baking powder, sugar, and salt.
Add the eggs and vanilla extract, and mix into a dough.
Fold the nuts into the dough.
Shape the dough into a long oval and place it on a parchment-lined baking tray.
Bake in the preheated oven at 180°C for 25 minutes.
Let cool, then slice into 1.5cm thick pieces.
Return the sliced biscotti to the oven and bake at 150°C (302°F) for an additional 10-15 minutes.