Instructions

• Preheat the oven to 375°F (190°C). Line three baking sheets with silicone mats or parchment paper.
• In a medium bowl, whisk together 2½ cups (312.5 g) all-purpose flour, 2 teaspoons cream of tartar, 1 teaspoon baking soda, and ½ teaspoon salt until evenly combined.
• Fit a stand mixer with the paddle attachment. Add ½ cup (113.5 g) softened unsalted butter, ½ cup (102.5 g) vegetable shortening, and 1½ cups (300 g) sugar to the mixer bowl. Beat on medium speed until the mixture is light and fluffy, about 3 minutes. Scrape down the bowl as needed.
• With the mixer running on medium-low, add the 2 eggs one at a time, beating each about 30 seconds until incorporated. Scrape down the bowl as needed.
• Reduce the mixer speed to low and slowly add the flour mixture. Mix until just combined, about 30 seconds. Finish mixing by hand with a spatula to ensure no dry flour pockets remain.
• In a small bowl or shallow dish, combine ¼ cup (50 g) granulated sugar and 1 tablespoon ground cinnamon to make the coating.
• Portion the dough using about 2 tablespoons per cookie (or a medium cookie scoop). Roll each portion into a ball, then roll the ball in the cinnamon-sugar to coat.
• Arrange the coated dough balls on the prepared baking sheets, about 8 cookies per sheet, leaving space between them for spreading.
• Bake one sheet at a time in the preheated oven until the edges are just set and beginning to brown but the centers are still soft, puffy, and cracked, 8 to 12 minutes. (The cookies may look slightly underdone between the cracks.)
• Allow the cookies to cool on the baking sheet for 10 minutes, then transfer them to a wire rack to cool completely.
• Store cooled cookies in an airtight container for up to 5 days.