Vegan mushroom and black bean burgers

by ILOVEVEGAN.COM (Brittany & William from Alberta, Canada). "In this recipe, I'm focusing on the food processor attachment with the chopping blade to chop all the veggies for my burgers," writes I Love Vegan. "There's lots of mushrooms, carrot, celery, red onion, and garlic, and I want them all chopped super fine and even. I'm also…