Preheat your oven to 350 degrees and line two baking sheets with either parchment paper or silicone baking mats. Set aside.
In a large bowl, add the melted (& cooled) butter, white sugar, and brown sugar and mix on medium until combined. (I used my hand mixer - stand mixer will def work, too)
1 stick salted butter, 1/2 cup sugar, 1/2 cup brown sugar
Add in the vanilla and egg and beat until just combined.
1 teaspoon vanilla, 1 egg
Add in the flour, baking soda, and salt and mix until a dough forms.