If using oven preheat the oven to 400 degrees
Cut the sweet potatoes into small cubes. Toss with olive oil, corn starch and spices.
Roast the sweet potatoes 15 minutes, toss and roast another 10-15 minutes until crisp. Alternatively you can roast in an air fryer for 10 minutes at 390 degrees, toss and roast an additional 5-10 minutes until crisp.
In a large skillet, heat 1 tablespoon of olive oil over medium heat. Saute the white onion for 3 minutes, stirring occasionally. Add the ground beef, breaking it up as you go. Drain off any grease. Add the taco seasoning, water and tomato paste. Stir well and cook until the mixture has thickened. Set aside.
Once the potatoes are tender and caramelized around the edges, remove from the oven.
Combine the sour cream and adobo sauce to make the chipotle cream.
Assemble the tacos by topping each sweet potato with the taco meat, chipotle cream, cheese, guacamole, pico de gallo and cilantro.