Melt the butter and the chocolate together. Either use a microwave or place a bowl over boiling water. When melted allow it to cool.
Preheat the oven to 180°C (160°C fan).
While it is cooling, combine the eggs and both the sugars. Whisk until the mixture is considerably lighter in colour. I used my electric mixer for this and it took several minutes.
Measure out the dry ingredients.
Combine the egg/sugar mix with the melted chocolate mixture.
Fold the dry ingredients into the wet ones. Do this gradually, through a sieve.
Fold in the nuts and the chocolate.
Divide up the mixture evenly in the cupcake cases in the tray.
Bake for 20 minutes, the top should be glazed and shiny.
Remove, allow to cool for a few minutes in the tray before transferring to a wire rack.
Once they have cooled, prepare the icing. Melt the chocolate and allow to cool.
Beat the butter until soft. Add in the sugar and vanilla essence.
Continue to beat. Scraping down the sides when needed.
Pour in the melted chocolate.
Add in the milk a little at a time. Beat until it’s thicker.
Recipe by The Bearded Bakery at http://www.thebeardedbakery.com/baking/cupcakes-muffins/chocolate-brownie-cupcakes/