Preheat the oven to 350℉ and lightly spray a nonstick mini muffin tin with cooking spray.
In a medium bowl stir together peanut butter, Sugar In The Raw Organic White Sugar®, flour, egg, vanilla, and salt. Scoop 1 scant tablespoon batter into each muffin cup and press evenly up the sides of the cups with your fingers or the narrow end of a wooden spoon.
In a medium bowl whisk together butter, cocoa powder, and Sugar In The Raw Organic White Sugar® until smooth. Whisk in egg and vanilla. Stir in flour and salt until combined. Spoon 1 rounded teaspoon batter into each peanut butter-lined muffin cup.
Bake until the brownie batter is set, about 12 minutes. Cool 5 minutes in the pan, then use a small spatula or thin knife to transfer to a rack to cool completely.