Step 1

In a medium bowl whisk together the flour, cream of tartar, baking soda, and salt. Set aside.

Step 2

Melt the butter in the microwave in 30 second increments. Set aside to slightly cool.

Step 3

In the bowl of a stand mixer, or in a large bowl with a hand mixer, use the paddle attachment and beat the butter, brown sugar, and shortening together until well combined, 3-4 minutes.

Step 4

With the mixer running, add the eggs 1 at a time with 30 seconds between the two eggs to fully combine.

Step 5

Turn the mixer speed to low and slowly add the flour mixture in.Continue mixing until just combined, about 30 seconds.

Step 6

Chill the dough in the refrigerator for 30-60 minutes.

Step 7

Preheat oven to 375°F.

Step 8

Mix the granulated sugar and ground cinnamon together in a small bowl.

Step 9

Scoop dough out in approximately 1.5 Tablespoon portions (I use a cookie scoop for this for fast and easy portioning!).

Step 10

Roll the dough ball in the cinnamon sugar mixture and place on a baking sheet.

Step 11

Fill the rest of the sheet, leaving space between each cookie (you can fit 12 on a sheet).

Step 12

Bake on the middle shelf for 8 minutes, rotating the sheet half way through.

Step 13

Let the cookies sit on the sheet for 10 minutes before moving to a cooling rack to cool completely.

Step 14

Repeat the process with the remaining dough. (Pop the dough back in the refrigerator if you are waiting between batches. Otherwise, portioning tray 2 while tray 1 is baking works perfectly!)

Step 15

Store in an air tight container for up to 1 week, or freeze up to 3 months.