Start by preheating your oven to 375°F (190°C). Line your cookie sheets with parchment paper or silicone baking mats to prevent sticking and ensure even baking. This step sets the stage for perfect cookies, so don’t skip it!

In a small bowl, mix together granulated sugar and cinnamon. This simple blend will coat the cookies, giving them that signature snickerdoodle flavor with a sweet and slightly spiced crunch.

In a medium bowl, whisk together flour, cream of tartar, baking soda, and salt. This dry mixture will give your cookies their classic texture. In a separate large bowl, use a hand mixer or a stand mixer with a paddle attachment to beat butter and granulated sugar at high speed until smooth and creamy (about 2 minutes). Add in an egg, an egg yolk, and vanilla extract, then mix at medium-high speed until fully combined. Scrape down the sides and bottom with a rubber spatula to ensure everything is evenly mixed. Lower the mixer to low speed and slowly incorporate the dry ingredients in three parts. The result? A thick dough that’s perfect for rolling.

Scoop cookie dough into balls, measuring about 1.5 tablespoons (35g) each. Using a cookie scoop makes this process much easier. Roll each dough ball in the cinnamon-sugar topping, ensuring a generous coating. If you love extra cinnamon flavor, sprinkle some more on top. Place the dough balls 3 inches apart on your baking sheets to allow room for spreading.

Bake the cookies for 10 minutes. They will come out puffy and soft, which is exactly what you want. While they are still warm, lightly press them down with the back of a spoon or a fork to flatten slightly. Let them sit on the baking sheet for 10 minutes before transferring them to a wire rack to cool completely.

To keep the cookies soft and fresh, store them in an airtight container at room temperature. They will stay delicious for up to 7 days, though they’re so good, they likely won’t last that long!