Preheat the oven to 400°F.
Scrub the sweet potatoes under running water and pat them dry with a paper towel.
Prick the sweet potatoes with a fork and place them on a baking tray lined with aluminum foil.
Bake the sweet potatoes for 45-60 minutes, depending upon the size, or until fork pierces easily through sweet potato.
While the sweet potatoes cook, prepare the filling. Mix the taco seasoning spices in a small bowl.
Heat a medium pan over medium high heat. Lightly grease the pan. Once hot, add onion and sauté until translucent, about 5 minutes. Add garlic, stir and cook for additional 2 minutes. Add the black beans, corn, diced tomatoes (and other additional items)
Note: if adding ground meat, be sure to brown and drain any liquid before adding the other items to the pan.
Mix the corn starch or arrowroot flour with the ½ cup water. Add the taco seasoning and water mixture to the pan. Stir and let simmer on low. You may have to add additional water if it gets too thick. Taste and adjust seasoning to your liking. If you like it more spicy add more chili powder.
When sweet potatoes are done, cut them in half. Mash the filling with a fork slightly. Then spoon taco mixture on top. Serve with your favorite toppings.
Optional Chipotle Aioli: place Greek yogurt, chipotle in adobo, honey and lime juice in a blender. Blend until smooth. Taste and adjust seasoning. If you want more spice add more chipotle in adobo, if its too spicy you can add more honey and lime juice. If it is too thick you can add a little water for a better consistency.