Preheat oven to 200C. Place baking paper over base of a flat baking pan.
Add maple syrup, oil, chilli and seasoning to a bowl and stir to combine. Toss with diced sweet potato until well covered. Spread over the prepared baking pan, evenly spaced out and roast for 35-40 minutes, or until caramelised and cooked through. It’s a good idea to turn them over around half way through but not completely necessary.
Once removed from the oven, use some tongs to move the pieces through the maple syrup mixture on the base of the pan.
Meanwhile, add oil, onion, garlic, spices and seasoning to a medium/large, heavy based saucepan. Bring to high heat then turn down to lowish heat and sauté with the lid on for 8 minutes, stirring regularly until onion is transparent.
Turn heat up to medium/high. Add tomato paste and cook down for a minute. Add tomatoes and bring to a simmer on medium heat and continue to cook, uncovered or with the lid to the side, for 15-20 minutes or until reduced a bit and thickened.
Just before the end of cooking time, add the black beans and stir to combine, heating through. Add further seasoning if you like.
Take off the hotplate and allow to sit uncovered for 5 minutes.
Layer the black bean mixture, a squeeze of lime juice, roast sweet potato, avocado, sour cream and herbs onto the soft tacos.
Serves: 4 (2 small tacos each)
Note: Black bean tomato filling can be made in advance or frozen.