In a large cast iron skillet, heat the oil over medium high heat. Add the onion and red bell pepper. Cook for 4 minutes or until tender, stirring occasionally. Add the garlic and cook for 1 more minute. Transfer to a plate and let cool to room temperature. Use a paper towel to blot excess moisture.

In a large bowl, add black beans and mash until mostly broken up with a few whole beans remaining.

Stir in the onion, pepper, and garlic. Add the egg, breadcrumbs, chipotle chili, chipotle sauce, cumin, chili powder, smoked paprika, salt, pepper, and cilantro. Mix until well combined.

Divide the bean mixture into 6 even portions and shape into 3/4-inch thick burger patties. Make sure the burger patties are as compact as possible; this will help prevent them from falling apart.

Preheat the cast-iron skillet over medium heat. Add a 1 to 2 tablespoons oil to the pan and cook the patties for 6 to 8 minutes per side, or until brown on both sides and the middles are set. If the patties start browning too fast on the outside, turn down the heat a little. Don’t overcrowd the pan, you will have to cook them in batches. I do 3 at a time.

Remove from heat. Place the black bean burgers on buns and top with desired toppings. Serve immediately.

Oven: Place patties on a parchment paper-lined baking sheet and bake at 375°F for 20 minutes, flipping halfway through.

Air Fryer: Air fry at 375 degrees F for 12 minutes, flipping halfway through, or until crispy and cooked through.