Vegan Mint Brownies (After Eight Brownies)

• 160 g plain/all-purpose flour (1 cup + 2 tablespoons)
• 80 g cocoa powder (⅔ cup)
• 250 g caster sugar (1+¼ cups)
• 1 Teaspoon baking powder
• 120 g Vegan margarine, melted (½ cup)
• 160 ml unsweetened soy milk (½ cup + 2 tablespoons)
• 1 Teaspoon peppermint extract
• 12 Vegan thin mints, roughly chopped (substitute for 150g/5.2oz of dark mint chocolate chunks or vegan chocolate chips)

For the icing (optional):

• 15 g vegan margarine (1 tablespoon)
• 70 g icing sugar (½ cup + 1 tablespoon)
• 1 Tablespoon unsweetened soy milk
• ⅛ Teaspoon peppermint extract
• Drop green food colouring (add in a small amount at a time until you get your desired colour)