Preheat oven to 350°
Prepare 2 baking sheets by lining with parchment paper.
In a medium bowl, whisk together flour, baking soda, baking powder and salt. Set aside.
Using a stand mixer with the paddle attachment or a hand mixer, begin creaming the butter, brown sugar and granulated sugar until light and fluffy (2 - 4 minutes on medium speed). Scrape the bowl as needed.
Add the egg to the bowl and mix on medium speed until incorporated. Scrape the bowl as needed.
Add the flour mixture and mix on low speed until combined.
Scoop 1 ½ tablespoon of the dough using a cookie scoop or spoon.
Place onto parchment-lined baking sheets leaving approximately 2 inches of space between each cookie.
Using your palm or the bottom of a round drinking glass, flatten the cookie slightly.
Bake cookies for 10 - 12 minutes.
Let cookies cool on the baking sheets for 5 to 10 minutes, then transfer them to a wire rack to cool completely.