Combine all ingredients (except powdered sugar) in a large bowl and stir until well combined
(Adding cornstarch is optional, but I've found that it always makes cookies a tad bit chewier, which is exactly how I like my cookies)
Allow dough to chill in refrigerator for about 1 hour
Preheat oven to 350 F
Pour about 1/2 cup of powdered sugar into a bowl, and roll a spoon full of cookie dough in your hands to create a ball - dough wil be very sticky
Place dough in powdered sugar and roll around until coated
Place on greased cookie sheet and bake for 10-12 minutes
Allow to cool on pan completely before serving
Enjoy!