Preheat oven to 375 F.

In a small bowl, combine potato starch, flour and salt.

Beat butter, vanilla and sugar until creamy.

Add flour mix a little at a time, until you have a homogenous cookie dough.

Wrap in plastic wrap and refrigerate for 2 hours.

Roll out dough on a well floured surface to about 1/2" thick. You don't even need a rolling pin. You can just pat it down using the palm of your hand. It's a very soft dough. Using cookie cutters, dip them in flour and then cut out cookies and place on parchment lined cookie sheet.

Bake for 15 minutes.