Brown the butter: In a light colored skillet or saucpan, melt the butter over medium heat, whisking occasionally. Once melted, the butter will begin to foam. Keep whisking occasionally. After 5-7 minutes, the butter will begin browning, and you’ll start to notice little brown specks at the bottom of the pan. Once browned, remove from heat immediately, pour into a heat proof bowl. Allow to cool to room temperature.

Preheat oven to 350°F and line 2 baking sheets with parchment paper or silicone baking mats.

Whisk the flour, baking powder, salt, and cornstarch together in a medium bowl. Set aside.

Cream the brown butter and brown sugar: Using a hand-held mixer or stand mixer with paddle attachment, beat together on medium-high speed until light and fluffy. Beat in the egg and vanilla extract.

Gradually add the dry ingredients into the wet ingredients until just combined.

Using a large cookie scoop, for the cookie dough into balls and roll into the granulated sugar. Place dough balls at least 2 inches apart on the prepared baking sheets.

Bake for 15-18 minutes or until lightly browned on the sides. Remove from the oven and allow to cool on the baking sheet for 5 minutes then transfer to cooling rack to cool completely.