Warm olive oil in a skillet set over medium-high heat. Add the onion and cook for 3-4 minutes, until beginning to soften, then add the garlic, cumin, chili powder, and a big pinch of salt. Cook for another 30-60 seconds, just until fragrant.

Stir in the beans, followed right away by the broth. Bring to a simmer, then reduce heat to medium and cook until the beans are slightly tender and most of the liquid has been absorbed—about 4 minutes.

Remove from the heat, then stir in the red peppers and set aside.

To assemble the quesadillas, place a clean skillet over medium-high heat and place a tortilla directly on the surface. Sprinkle a thin layer of cheese evenly over the surface of the tortilla, followed by a thin layer of the bean mixture. Finish with an additional thin layer of cheese, then top with another tortilla.

Using a spatula, gently press down on the top tortilla, and cook until the cheese is melted. Gently flip the quesadilla and cook for 1-2 minutes more. Remove to a cutting board and continue with additional tortillas as desired.

Slice into quarters and serve with salsa, sour cream, cilantro, guacamole, or lime wedges as desired.