question: What is a good beer pairing for Roast beef with a herb and malt crust?
answer: A great choice for Roast beef with a herb and malt crust is Paradox Islay 2018 (Whisky Cask Aged Imperial Stout.). Here's the recipe:
  A Whisky Cask Aged Imperial Stout. with 13.5% ABV. Uses 7 malts and 4 hop varieties. Brewing tip: Brew this as part of a parti gyle mash, making this beer from your first runnings. It will take a long time to run off and be prepared to add dextrose to reach your target OG.