Step 1: Preheat the Oven - Begin by preheating your oven to 350°F (175°C). This ensures your cookies bake evenly.
Step 2: Prepare the Cinnamon Sugar - In a small bowl, mix together 1/3 cup granulated sugar and 1 teaspoon of cinnamon. Set aside for rolling the cookies later.
Step 3: Cream the Butter and Sugars - In a large mixing bowl, beat together the room temperature unsalted butter, 1 and 1/2 cups granulated sugar, and 1/3 cup cinnamon sugar mixture until light and fluffy, about 2-3 minutes.
Step 4: Add the Eggs and Vanilla - Add in the large egg, the egg yolk, and the vanilla extract. Beat until well combined, scraping down the sides of the bowl as necessary.
Step 5: Combine the Dry Ingredients - In another bowl, whisk together the all-purpose flour, cream of tartar, baking soda, ground cinnamon, and salt. Gradually add this dry mixture to the wet ingredients, mixing until just combined.
Step 6: Fold in the White Chocolate Chips - Gently fold in the white chocolate chips with a spatula, ensuring they are evenly dispersed throughout the dough.
Step 7: Roll the Dough - Using a cookie scoop or your hands, scoop out about 2 tablespoons of dough and roll it into a ball. Roll it in the cinnamon sugar mixture prepared earlier.
Step 8: Bake the Cookies - Place the rolled dough balls on a lined baking sheet, leaving space between each cookie. Bake in your preheated oven for 10-12 minutes, or until the edges are lightly golden.
Step 9: Cool and Enjoy - Once baked, remove the cookies from the oven and let them cool on the baking sheet for about 5 minutes before transferring them to a cooling rack. Enjoy these White Chocolate Chip Snickerdoodles warm or store them for later!
