This is the recipe OP was replying with previously.

INGREDIENTS
1½ cups/180 grams all-purpose flour
1 teaspoon cream of tartar
½ teaspoon baking soda
½ teaspoon kosher salt
10 tablespoons/140 grams unsalted butter (1¼ sticks), at room temperature
3/4 cup/150 grams granulated sugar, plus 2 tablespoons
1 large egg
1/2 teaspoon vanilla extract
1 tablespoon ground cinnamon

PREPARATION

1. Heat the oven to 375 degrees. In a medium bowl, whisk together the flour, cream of tartar, baking soda and salt.

2. In the bowl of an electric mixer, beat together the butter and ¾ cup sugar until fluffy, about 2 minutes, scraping down the sides as necessary. Beat in the egg until creamy, and then add the vanilla, again scraping down the sides. Add the flour mixture to the butter mixture and beat on low until just combined.

3. In a small bowl, combine the remaining 2 tablespoons sugar and the cinnamon. Roll the dough into golf-ball-size balls, then roll each one in the cinnamon-sugar mixture.

4. Transfer the dough to parchment-lined rimmed baking sheets, at least 3 inches apart. Bake the cookies until just set and dry in the center, 10 to 12 minutes. Do not overbake. Transfer each sheet to a rack to cool for a few minutes, then transfer the cookies to racks to cool completely.

...but they're just snickerdoodles, they just took care to make sure that they are completely covered in cinnamon sugar to look good in the photo.

The inside looks like every snickerdoodle I've ever had.