Preheat the oven to 175°C.
Combine the oil, sugar and eggs in a large bowl. Mix together the flour, baking powder, ginger, cinnamon, cloves and nutmeg in another bowl. Combine all the dry ingredients and stir into the egg mixture. Divide the dough into two and shape each half into a roll.
Place the rolls on a baking tray lined with baking parchment and flatten out the doughs a little.
Bake in the oven for 20 minutes. Remove from the oven and leave aside to cool for about 10 min.Cut the dough diagonally into 2 cm thick slices.
Return them onto the baking tray and bake for another 5−7 minutes on each side.
Switch the oven off and allow the biscotti to dry for 2 hours in the residual heat.