In a bowl, combine together all purpose flour, corn flour and salt. Keep it aside.
In another bowl, beat together unsalted butter and ¼ cup powdered sugar till creamy. To this add vanilla essence and beat well. Add the flour mixture to this little by little and beat till evenly combined. Knead this to a smooth dough for a minute and refrigerate it for an hour covered with a cling wrap.
Remove the dough from the refrigerator and make 22 – 25 lemon sized balls and place them in a greased baking sheet (baking tray) spacing them in between.
Preheat the oven to 180 degree and bake the cookies for about 15 – 17 minutes or till the edges of the cookies turn golden brown. Remove the cookie sheet from the oven and slowly remove the baked cookies to a wire rack. Let it cool for about 5 – 6 minutes.
Take a parchment paper, sprinkle 3 tbsp powdered sugar all over that and place the baked cookies over that (so the base of the cookies are coated with powdered sugar). Now sprinkle the remaining powdered sugar all over the cookies and again move it to the wire rack. Cool it completely and store it in an air tight container. Serve.