01 - Preheat the oven to 425°F. Line a baking sheet with parchment paper.
02 - In a large bowl, toss diced sweet potatoes, sliced onion, and chopped bell pepper with olive oil, cumin, smoked paprika, chili powder, coriander, salt, and black pepper until evenly coated.
03 - Spread the seasoned vegetables evenly on the prepared baking sheet. Roast for 25 to 30 minutes, tossing halfway through, until tender and slightly caramelized. Remove from oven and let cool for 5 minutes.
04 - In a large skillet over medium heat, warm the black beans with minced garlic for 2 to 3 minutes, stirring occasionally until heated through.
05 - Warm the tortillas in a dry skillet or microwave until pliable.
06 - Layer roasted vegetables, black beans, shredded cheese if using, avocado slices, and a spoonful of sour cream or Greek yogurt onto each tortilla. Sprinkle with chopped cilantro.
07 - Fold in the sides of each tortilla and roll up tightly to enclose the filling.
08 - Place burritos seam-side down in a skillet over medium heat and toast for 2 to 3 minutes per side until golden and crisp, if desired.
09 - Serve the burritos hot with lime wedges on the side.