Bake Brownie as per packet instructions, adding in chilli powder with dry ingredients and bake until 3⁄4 cooked so it’s nice and oozy.
Add nuts, sugar, and butter to a large non-stick skillet and heat over medium heat. Stir constantly with a rubber heat-proof spatula until the sugar melts into the butter and completely coats the nuts, turning the heat down as needed, approximately 5-7 minutes.
Immediately transfer nuts to parchment paper let the nuts cool and harden and chop with a knife once cooled.
Tear brownie and plate, top with ice-cream and caramelised nuts.