Line 2 large baking trays with baking paper and set aside for later.
In a small saucepan, add butter and melt over a gently heat (don’t allow to boil). Remove from heat and stir in dark chocolate. Most of the chocolate will melt but you may need to return the saucepan to a very low heat to completely melt it, remove from heat and set aside.
Place the castor sugar, eggs, cocoa powder and vanilla extract in the bowl of an electric mixer and beat for 3 – 4 minutes on a very slow speed.
Slowly pour the chocolate mixture into this mixture as it continues to beat and turn off the electric mixer once well combined.
Add the baking powder and plain flour and mix with the electric mixer for 1 minute.
Remove the bowl from the mixer, add the crushed peanuts and stir through until well distributed.
Drop tablespoons of mixture onto the trays, leaving a very large gap between each biscuit as they will spread. I use large cookie trays and only cook 6 biscuits at a time.
Bake for approximately 12 minutes. Remove from oven and allow biscuits to cool on the baking trays for another 5 minutes. Transfer biscuits to a wire rack to cool completely.
These biscuits can be stored in an air-tight container for up to 5 days.
Recipe by Mrs Organised at http://www.mrsorganised.com.au/2015/10/16/choc-peanut-brownie-biscuits/