Preheat your oven to 325 F and line 2 cookie sheets with parchment paper.
With an electric mixer, beat the butter, salt and sugar on medium-high speed until light and fluffy.
Using your hands, mix in the flour and corn starch for about 10 minutes until the mixture is well mixed together.
Separate the dough into two pieces, and roll out each ball on a floured surface (sprinkle some flour on top of your dough too) using a rolling pin until the dough is about 1/4" thick.
Cut out your desired shapes with a cookie cutter or use a cookie press (see notes above), place on a cookie sheet lined with parchment paper and bake for about 15 minutes until they are very lightly browned. Cool on a wire rack.