https://www.youtube.com/watch?v=sNJN7a_yghY

12.5 oz (2 1/2 C) all purpose flour
2 t cream of tartar
1 t baking soda
1/2 t salt
8 T (4.0 oz) softened unsalted butter
8 T (3.6 oz) vegetable shortening
10.5 oz (1 1/2 C) sugar plus 1/4 cup for rolling
2 large eggs
1 T cinnamon

Adjust oven rack to middle position and heat oven to 375 degrees. Line 3 
baking sheets with parchment paper. Whisk flour, cream of tartar, baking 
soda, and salt together in bowl.

Using stand mixer fitted with paddle, beat butter, shortening, and 1 1/2 
cups sugar together on medium speed until light and fluffy, about 3 minutes. 
Beat in eggs, one at a time, until incorporated, about 30 seconds, scraping 
down bowl as needed.

Reduce speed to low and slowly add flour mixture until combined, about 30 
seconds. Give dough final stir by hand to ensure that no flour pockets remain.

Combine remaining 1/4 cup sugar and cinnamon in shallow dish. Working with 
2 tablespoons dough at a time, roll into balls, then roll in sugar to coat; 
measure and space 2 inches apart on prepared baking sheets. (Raw cookies can 
be frozen for up to 1 month; bake frozen cookies in 300-degree oven for 18 
to 20 minutes.)

Bake cookies, 1 sheet at a time, with 8 cookies per sheet, until edges are 
just set and beginning to brown but centers are still soft, puffy, and 
cracked (cookies will look raw between cracks and seem underdone), 8-12 
minutes, rotating sheet halfway through baking. Let cookies cool on sheet 
for 10 minutes, then transfer to wire rack and let cool completely before 
serving.