Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a saucepan over medium heat, melt the butter. Stir continuously until it turns golden brown with a nutty aroma, around 5 to 7 minutes. Let it cool slightly.

In a large mixing bowl, combine the browned butter with granulated and brown sugars until smooth.

Add the eggs and vanilla extract, stirring until fully incorporated.

In a separate bowl, whisk together the all-purpose flour, cream of tartar, baking soda, and salt.

Gradually add the dry mixture to the wet mixture, stirring until just combined to avoid overmixing.

In a small bowl, mix the sugar and cinnamon for rolling.

Scoop the dough into small balls, rolling each in the cinnamon-sugar mixture before placing them on the prepared baking sheet.

Bake for 10-12 minutes until the edges are lightly set and the centers are soft.

Let them cool on the baking sheet for a few minutes before transferring to a wire rack.