Sift flour, salt and icing sugar together into a large bowl. Add in the pea powder and mix all the ingredients thoroughly. Add oil sparingly and slowly mix till the dough does not stick to the hands.Let dough rest for 15 minutes, covered.Roll dough into small balls, press hard (about 10-12g each) and arrange them on a parchment lined baking tray. Apply egg glaze.Bake in a preheated oven at 180 degrees C for 15 minutes.Allow cookies to cool on tray for about 10 minutes before removing them onto a wire rack to cool completely before storing into an airtight container.