In the bowl of a stand mixer with paddle attachment, blend sugar, butter, egg, and vanilla on low to just combine. Switch mixer to medium-high and mixer for about 3 minutes, or until light a fluffy.
While that is mixer place flour, cake flour, cornstarch, baking powder and baking soda into a bowl and whisk together.
With the mixer on low speed, slowly add dry ingredients into the butter mixture. Mix until just combined.
Remove bowl from mixer and add in pinch of salt. With a rubber spatula, scrape down sides of bowl and gently mix ingredients.
Using a small ice cream scoop, scoop out balls of sugar cookie and place on a parchment lined baking sheet close together.
Do this until all the dough is gone; you should have about 24 sugar cookie dough balls.
Place in freezer for at least one hour. (if freezing for longer make sure the sugar cookie dough is sealed in an air tight container until ready to use)
When ready to bake heat oven to 350 degrees F. (325 in convection ovens)
Place dough ball (can still be frozen) on parchment lined baking sheet 2 inches apart from each other.
Bake for 7-10 minutes, or until no longer "wet" looking in the center. These cookies are best when slightly under-done.