In a small bowl whisk the all-purpose flour, granulated sugar and salt. Add the melted butter and combine. Spread shortbread dough evenly across bottom of a parchment lined 8×8 pan and bake.
Melt the butter in a small pot over low heat. While still on heat, add both sugars. Once they’re dissolved, whisk in cocoa powder. Remove from heat and set aside.
Pour brownie batter into a parchment lined 8x8 inch pan. Bake brownies for 20-25 minutes or until the center is just set. Cool brownies to room temperature before slicing.