1cup(2 sticks) unsalted butter, at room temperature
1and 1/2 cups granulated sugar
1large egg plus 1 egg yolk
1and 1/2 teaspoons vanilla extract
2and 1/2 cups all-purpose flour
1and 3/4 teaspoons cream of tartar
2cupswhite chocolate chips
For the cinnamon sugar topping:
In a small bowl combine the granulated sugar and cinnamon; set aside until needed.
For the snickerdoodle cookie dough:
Preheat oven to 375 degrees (F). Line two large baking sheets with parchment paper or silicon baking sheets; set aside.
In a large bowl using a hand-held mixer or using a stand mixer fitted with the paddle attachment, cream the butter on medium speed until completely smooth, about 1 minute. Add in the sugar and continue beating on medium speed until light and fluffy, about 2 minutes. Add in egg, yolk, and vanilla and beat smooth, scraping down the sides as needed. Set bowl aside.
In a medium-sized bowl whisk together the flour, cream of tartar, baking soda, cinnamon, and salt. Slowly add the dry ingredients to the wet ingredients, all at once, and stir the dough together using a rubber spatula. Stir in the white chocolate chips. The dough will be quite thick. Stir just until combined - being sure not to over mix.
Using an ice cream scoop, melon baller, or measuring spoon, take one and a half sized tablespoons of dough from the bowl and roll it into a ball. Roll the dough ball into the cinnamon sugar topping, then transfer the ball onto prepared baking sheet. Repeat with all cookie dough. Bake cookies, one tray at a time, for 9-10 minutes. The cookies will be set at the edges and very soft. While they are still very warm, lightly press down a few white chocolate chips on top, if desired. Allow cookies to cool on the baking sheet for 10 minutes before serving warm or transferring to a wire rack to cool completely.
1) Cookies will stay fresh for 5 days when stored in an airtight container at room temperature. 2) These cookies freeze great! You can freeze the baked cookies for up to 2 months. You can also freeze the rolled cookie dough balls for 2 months. When you bake the frozen cookie dough balls, add 2 minutes to the called for bake time.