Step 1

Adjust the oven racks for roasting two trays. Preheat the oven to 450 degrees Fahrenheit.

Step 2

Slice the onion and slice the bell pepper into wide slices. Chop the sweet potato. Place it in a large bowl with the black beans (drained and rinsed).

Step 3

Mix in the olive oil, cumin, chili powder, garlic powder and kosher salt and stir until everything is evenly coated. Line two baking sheets with parchment paper (we prefer this to silicone baking mats because it results in crispier veggies). Spread the vegetables evenly onto each sheet.

Step 4

Place the sheets into the oven and bake for 20 minutes (do not stir!). Remove the pans from the oven, rotate them, and roast another 10 minutes (for 30 minutes total) until tender and lightly browned on one side. Cut the lime into wedges and spritz the veggies with fresh lime juice to taste (2 wedges per sheet).

Step 5

Warm and char the tortillas by placing them on an open gas flame on medium for a few seconds per side, flipping with tongs, until they are slightly blackened and warm. (See How to Warm Tortillas.)

Step 6

Top the tortillas with the roasted vegetables, pico de gallo and cheese crumbles, if using. Top with sour cream or the alternative sauces, and chopped cilantro.