01 - Set the oven to 425°F and line a baking sheet with parchment paper.
02 - In a large bowl, toss the diced sweet potatoes, red onion, and red bell pepper with olive oil, salt, and pepper until evenly coated.
03 - Spread the vegetable mixture evenly on the baking sheet and roast for 20 to 25 minutes, stirring halfway through, until the sweet potatoes are tender and caramelized.
04 - In a mixing bowl, gently combine the roasted vegetables, black beans, shredded cheese, cilantro (if using), cumin, smoked paprika, and chili powder.
05 - Lay out the tortillas and spread one-quarter of the filling over half of each tortilla. Fold them over to enclose the filling.
06 - Heat a large non-stick skillet over medium heat and lightly grease with oil or cooking spray. Cook two quesadillas at a time for 2 to 3 minutes per side until golden brown and the cheese has melted.
07 - Slice the cooked quesadillas into wedges and serve warm, optionally accompanied by salsa, sour cream, or guacamole.