- Preheat oven to 350 and line two baking sheets with parchment paper.
- Melt the butter in a skillet over medium heat. Allow to simmer until it starts to turn an amber color and smell nutty and fragrant. Remove from the heat to a separate bowl. Allow to cool for 15 minutes.
- In the bowl of a stand mixer fitted with a paddle attachment, combine the browned butter and brown sugar until well-blended.
- In a separate bowl, whisk together the flour, baking soda, baking powder, and salt. Set aside.
- Add the egg and egg yolk to the butter/sugar mixture one at a time, scraping down the sides after each addition. Mix in the vanilla.
- Mix the flour mix into the cookie dough, stirring until just combined.
- In a small bowl, combine the sugar and brown sugar.
- Scoop the cookie dough into balls using a 1½ tbsp cookie scoop (or just scoop it into rounded tbsps). Roll in the sugar mix and place on the prepared baking sheet. Repeat with remaining cookie dough, leaving 2 inches between each dough ball on the baking sheet.
- Bake for 10-12 minutes or until starting to set around the edges. Allow to cool before serving.
Source: http://joanne-eatswellwithothers.com/2013/10/brown-sugar-cookies.html