Prepare the Black Beans
In a large mixing bowl, place the drained and rinsed black beans. Use a fork or potato masher to mash the beans, aiming for a thick texture with some whole beans remaining. This will provide texture to the patties. If using a food processor, pulse the beans a few times, but do not puree them completely.

Add Flavoring Ingredients
Add the finely chopped onion, minced garlic, cumin, chili powder, smoked paprika, and soy sauce to the mashed beans. Stir well to combine, ensuring that the spices are evenly distributed throughout the mixture.

Bind the Mixture
Add breadcrumbs and egg (or flax egg for a vegan version) to the mixture. The breadcrumbs will help bind the mixture together, and the egg acts as a binding agent. Stir until the mixture forms a thick, sticky consistency. Season with salt and pepper. If the mixture feels too wet, add more breadcrumbs, one tablespoon at a time, until you achieve the right texture.

Form the Patties
Take a small handful of the mixture and shape it into a round patty, about 1/2 inch thick. Repeat this process until all the mixture is used, yielding about four patties.

Cook the Patties
Heat 2 tablespoons of olive oil in a skillet over medium heat. Once the oil is hot, carefully add the patties. Cook each patty for about 4-5 minutes on each side, or until golden brown and crispy. Alternatively, you can grill the patties for 4-5 minutes per side, ensuring the burgers are firm on the outside.

Assemble the Burger
Toast the buns lightly for added crunch. Place a patty on the bottom half of each bun. Top with your favorite toppings such as lettuce, tomato, pickles, avocado, or cheese. Add condiments like mustard or ketchup, and top with the other half of the bun.