1) Collect in the mixer the flour, the cold butter into cubes, the grated lemon zest, a pinch of salt and a generous grinding of pepper. Blend until you get a mixture of crumbs. Add 3-4 tablespoons of ice water and run the mixer again for a few moments. Transfer the mixture in a bowl and stir in the pumpkin seeds.
2) On a sheet of baking paper modeled the dough in a cylinder of about 6 cm in diameter, wrap it in paper and put it in the fridge for 1 hour.
3) Eliminate paper and cut the cylinder into 7 mm thick slices: you will get about 40 biscuits. Arrange them on 2 plates lined with baking paper e cook them in a static oven at 180 ° for 10 minutes, then switch to ventilated mode and continue cooking for 5 minutes. Remove the cookies from the oven and let them cool.