question: What is a good beer pairing for Chocolate and walnut brownie?
answer: A great choice for Chocolate and walnut brownie is Brixton Porter (Paradigm-Changing Porter.). Here's the recipe:
  A Paradigm-Changing Porter. with 5% ABV. Uses 6 malts and 3 hop varieties. Brewing tip: After the primary fermentation has finished, leave the beer in contact with the yeast for around 48 hours. Any longer and there is a risk that it will start to impart yeasty, bready flavours to the beer.