Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper.
In a large mixing bowl, cream together the softened butter and 1 1/2 cups sugar using an electric mixer or whisk until the mixture is light, fluffy, and pale, about 2-3 minutes. You should hear a gentle whir and see the mixture turn creamy.
Add the eggs one at a time, mixing well after each addition. The mixture will become smooth and slightly thicker, with a glossy appearance.
In a separate bowl, whisk together the sifted flour, cream of tartar, baking soda, and salt. This ensures even distribution of leavening agents and salt.
Gradually add the dry ingredients to the wet mixture, mixing on low speed until just combined. The dough should be soft but manageable, with no streaks of flour remaining.
In a small bowl, mix together the 1/4 cup sugar and 2 teaspoons cinnamon for the coating.
Use a cookie scoop or tablespoon to portion out about 1 1/2-inch balls of dough. Roll each ball in the cinnamon-sugar mixture until evenly coated.
Place the coated dough balls onto the prepared baking sheet, spacing them about 2 inches apart. Gently flatten each ball slightly with your fingers or the bottom of a glass to encourage even baking.
Bake in the preheated oven for 10-12 minutes, until the edges are golden brown and the tops are crackly. The cookies will smell warm and cinnamon-y, inviting you to wait patiently.
Remove the cookies from the oven and let them rest on the baking sheet for about 5 minutes. Then, transfer them to a cooling rack to cool completely, allowing the centers to set and develop their chewy texture.
Enjoy your snickerdoodles warm or at room temperature, perhaps with a glass of milk, and savor that nostalgic cinnamon aroma and crispy-chewy bite.
