The addition of black garlic and Guinness, along with porcini mushrooms give this burger an earthy *meat* flavour. The addition of TVP gives the burgers a meaty texture. Black garlic is easy to make from fresh garlic bulbs. The easiest and less odorous way I've found is to pop them into roasting bags and put them into your slow cooker on a yogurt heating. It takes over a week, but it's much cheaper than buying them already made.