01 - Preheat oven to 425°F and 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 and roast for 25 to 30 minutes, stirring halfway through, until tender and caramelized. Remove from oven and let cool for 5 minutes.
04 - In a skillet over medium heat, warm the drained black beans with minced garlic for 2 to 3 minutes, stirring occasionally until heated through.
05 - Heat the flour tortillas in a dry skillet or microwave until soft and pliable.
06 - Layer roasted vegetables, warmed black beans, shredded cheese if using, avocado slices, and a dollop of sour cream or Greek yogurt on each tortilla. Sprinkle with fresh cilantro.
07 - Fold the sides of each tortilla inward and roll tightly to encase the filling.
08 - For a crisp exterior, place burritos seam-side down in a skillet over medium heat and toast for 2 to 3 minutes per side until golden brown.
09 - Serve hot with lime wedges on the side.