01 - Place the drained black beans in a large mixing bowl and mash with a fork or potato masher until coarsely broken down, leaving some texture intact.
02 - Add the grated carrots, chopped mushrooms, diced red onion, corn kernels, minced garlic, parsley, rolled oats, breadcrumbs, smoked paprika, cumin, salt, and pepper to the mashed beans.
03 - Crack in the egg (or add the prepared flax egg) and mix thoroughly until all ingredients are evenly distributed and the mixture holds together when pressed.
04 - Divide the mixture into 4 equal portions and shape each into a patty approximately 1 inch thick, pressing firmly to compact.
05 - Heat the olive oil in a large skillet over medium heat. Cook the patties for 4 to 5 minutes per side until golden brown and cooked through.
06 - Toast the burger buns cut-side down in the skillet for about 1 minute until lightly golden.
07 - Layer each bun with a patty, lettuce leaves, tomato slices, pickles, and your preferred condiments. Serve immediately.