In a medium bowl, combine together the flour, cream of tartar, cornstarch, baking powder, and salt. Set aside.

In a large bowl, add the butter and sugar and use an electric hand mixer to cream for 2-3 minutes until light & fluffy. Add egg, egg yolk, and vanilla and mix until fully combined.

Lastly, add the dry ingredients and mix on low speed until just combined.

Remove half of the cookie dough and place in a separate medium bowl. I recommend weighing it with a scale to ensure you get exactly half of the cookie dough.

To one of the bowls of cookie dough, add the molasses, flour, and spices. Mix on low speed until just combined.

Use two 1.5 tablespoon cookie scoops to portion each cookie dough onto one baking sheet.

Take one plain cookie dough ball and one molasses cookie dough ball, and divide each in two, then stack them in four alternating layers. Roll the cookie dough into a smooth ball and place back on the baking sheet.

Once all of the cookie dough has been rolled, place the baking sheet in the freezer for at least 15 minutes.

Meanwhile, preheat the oven to 325 degrees F. Make the spiced sugar by combining the sugar, cinnamon, and ginger in a small bowl.

Roll each frozen cookie dough ball in the spiced sugar and place a large baking sheet spaced about two inches apart.

Bake the cookies for about 14-16 minutes or until the edges are just turning golden.

Remove the cookies from the oven and immediately use a round cookie cutter or glass to scoot the edges of each cookie, making them perfectly round.

Allow the cookies to cool completely on the baking sheet.