1. Cook sweet potato
Check your avocado is ripe before starting this recipe (see Kitchen notes). Preheat the oven to 220C, fan-forced. Grease a 1.5L (6 cup) baking dish. Cut the unpeeled sweet potato into 3cm chunks. Put the sweet potato in a small saucepan, cover with cold salted water and bring to the boil. Reduce the heat to medium and cook for 8-10 mins until tender. Drain.
2. Make filling
Meanwhile, coarsely grate the cheese. Drain and rinse the beans. Put the cooked sweet potato and beans in a large bowl and coarsely mash. Add the Tex-Mex seasoning and 2 tbs of the tomatoes and stir to combine. Taste, then season with salt and pepper.
3. Assemble enchiladas
Put the tortillas on a clean work surface. Spoon the bean filling down the centre of each tortilla and roll to enclose, then put in the baking dish, seam-side down.
4. Bake enchiladas
Spoon half the remaining tomatoes* over the enchiladas. Season with salt and pepper, then scatter with the cheese. Bake for 14 mins or until golden and the cheese is melted.
5. Serve up
While the enchiladas are baking, coarsely chop the avocado (see Kitchen notes). Top the enchiladas with the avocado and season with salt and pepper. Divide among plates or pop the dish on the table for everyone to help themselves. Enjoy!
6. Kitchen notes
To speed up the ripening process, put the avocado in a paper bag and loosely close, then leave on the kitchen bench for a day or two. Add a banana to the bag to make the avocado ripen faster. ~ Fancy guac instead? Mash the avocado, then season with salt and pepper. Stir in a spoonful of sour cream for a luxe touch.