Heat olive oil in a skillet over medium heat; cook and stir diced red bell pepper, red onion, and garlic in the hot oil until soft, 5 to 7 minutes.

Combine the bell pepper mixture, black beans, mustard, flour, chili powder, cumin, salt, and black pepper in a food processor; blend until the beans are completely mashed.

Form the mixture into 2 patties.

Cook the patties in a skillet over medium heat until heated through, 4 to 5 minutes per side.