Design Eat Repeat

0 Preheat oven to 350°F.
2 In a microwave-safe bowl, melt the unsalted butter ([adjustable]½ cup, i.e. 1 stick[/adjustable]) for 30-60 seconds or until fully melted (you don't want any lumps).
3 Add in granulated sugar ([adjustable]¼ cup) and light brown sugar (½ cup[/adjustable]) and use a spatula to stir until combined (*do not use a mixer!). Add in egg ([adjustable]1[/adjustable] large) and vanilla extract ([adjustable]2 teaspoons[/adjustable]), then mix. Next, mix in baking soda ([adjustable]½ teaspoon), cream of tartar (½ teaspoon), and salt (¼ teaspoon). Add in all-purpose flour (1 ½ cups[/adjustable]) and mix just until all the flour disappears into the dough.
14 In a small bowl, mix together the granulated sugar ([adjustable]3 tablespoons) and cinnamon (1 tablespoon[/adjustable]). 
13 Scoop dough into 3-tablespoon-sized scoops (I use this stainless steel cookie scoop!), roll into balls, then coat in the cinnamon sugar mixture.
15 Place on a light metal pan with parchment paper (the light metal will help them spread; dark metal pans will likely result in a puffier cookie).
11 Bake at 350 for 10-11 minutes. Do not overbake. The cookies will continue to bake on the hot pan, allowing them to firm up without overbaking.*If your cookies puff up a bit, immediately tap the pan on the counter a few times to help them deflate. You want to do this immediately after removing from the oven. You can also flatten the tops of the dough balls for the next pan to help them spread.
12 Allow to cool, then enjoy!