These treats get their name from their shortbread cookie base.
Heat the oven to 350°F (175°C).
Line a 9×13 inch pan with parchment paper.
In a large bowl, mix together flour, baking soda, salt and brown sugar, making sure to break up any lumps.
Add melted butter into the dough and mix until combined.
Press the mixture into the base of the pan evenly and bake for 20 minutes until golden and slightly firm to the touch.
Let base cool completely while you make the ganache.
Place white chocolate and cream into a microwaveable bowl, microwave and stir until completely melted and smooth.
Mix peanut butter, salt and peanuts in a bowl.
Add melted white chocolate mix to peanut butter and mix until combined.
Once your base is completely cool, pour the ganache over top and spread it out evenly.
Put the pan in the fridge for at least two hours until ganache fully sets.
To serve, slice into triangles (brownie square size cut again diagonally) and dip the longer side into melted dark chocolate and roasted peanuts.