Preheat the oven to 350 degrees F (175 degrees C) and spray a mini cupcake pan with non-stick baking spray.
Add the butter and sugar to a medium pot over a medium heat and stir until it’s all melted together and the sugar dissolves, then stir in the vanilla and set aside to cool slightly.
Whisk in the eggs, then sift in the cocoa powder and flour and stir to combine.
Spoon the brownie mix into the mini cupcake pan and bake for 10 minutes or until the edges are set.
Allow to cool in the pan for a few minutes, then remove the brownie bites from the pan and allow to cool completely on a wire rack.
Mix the powdered icing sugar with a few drops of water to form a thick paste. Use it to ‘glue’ the candy eyes to the brownie bites.