WET INGREDIENTS: Place the butter in a large bowl and melt in the microwave. Set the bowl aside to cool to room temperature. If the butter/bowl is warm or hot, it will melt the sugars and cause greasy cookies. Once completely cool, add in the white sugar and brown sugar. Whisk together briskly until creamy. Add in 1 whole egg and 1 egg yolk (reserve the whites for a separate recipe or discard) and the vanilla extract. Whisk until just combined and smooth.
DRYINGREDIENTS: In another bowl, stir together the flour, cornstarch, salt, baking soda, and 1 teaspoon ground cinnamon. Whisk together.
DOUGH: Add all of the dry ingredients into the wet ingredients and, using a strong wooden spoon, mix until JUST combined. Do not over mix the dough. Roll balls of dough that are 1 and 1/2 tablespoons in size. Roll the balls tall instead of wide (see pictures in post; See Note 2). In a small bowl, stir together the white sugar and cinnamon. Roll the balls of dough generously into the cinnamon-sugar mixture. Reserve the rest of the cinnamon-sugar mixture for later.
CHILLDOUGH: Place dough balls on a parchment or Silpat-lined sheet pan or plate and chill for 1 hour.
BAKE: Preheat the oven to 325 degrees F (162°C) Place 6 cookies at a time on a parchment or Silpat-lined sheet pan (they need a good amount of room) and bake straight from the fridge for 9-11 minutes. Gently remove from the oven so they don't deflate, let stand on cookie sheet for 5 minutes and then gently remove to a cooling rack.
FROSTING: Meanwhile, prepare the frosting. In a large bowl, beat the room-temperature butter and cream cheese until completely smooth. mix in the vanilla and salt. Add in the powdered sugar and then beat until the frosting is smooth (it will seem like you need more liquid, but just keep beating; it will come together!
FROSTCOOKIES: Transfer the frosting to a plastic bag or piping bag and cut off the tip. Frost each cooled cookie by piping the frosting in a swirl on top. Sprinkle tops of the cookies with leftover cinnamon sugar mixture.
Video
Notes
Note 1: If you press a measuring cup into a bag of flour and scoop, you will pack in way too much flour, resulting in the wrong texture of cookie. To properly measure the flour, use a spoon to spoon the flour into the measuring cup until its overfilled. Then use the back of a table knife to level the measuring cup at the top. (Video visual here).Note 2: Instead of rolling a perfectly round ball, roll the dough so it’s taller and skinnier. When the cookies bake you’ll get that perfect thick and chewy center and the crisp edges. Using this technique, the bottom of the cookie ball bakes first, which will push out and become the crisp edge. The top of that tall cookie dough ball then becomes the thick and chewy center. Perfect texture every time!