Remove a rack from the oven (see cooking tip). Preheat the oven to 200C, fan-forced. Thinly slice the onion. Combine 1 tsp sugar and 2 tsp red wine vinegar in a bowl. Add the onion and toss to coat. Set aside to pickle, tossing occasionally, until needed. Finely chop the tomato.
Step 2 — Brown plant-based mince
Heat 2 tsp olive oil in a medium frypan over medium-high heat. Cook the plant-based mince, breaking up the lumps with a spoon, for 5-6 mins until browned. Add the tomato and cook, stirring, for 1-2 mins until starting to soften.
Step 3 — Finish mince
Add the Tex-Mex seasoning, barbecue seasoning, barbecue sauce and tomato paste to the mince mixture and cook, stirring, for 30 secs or until fragrant. Add 60ml (¼ cup) water and cook, stirring, for 1-2 mins until slightly thickened. Stir in 1 tsp red wine vinegar. Taste, then season with pepper.
Step 4 — Bake taco shells
While the mince mixture is cooking, drape the tortillas over an oven rack to shape into taco shells. Put the rack into the oven and bake the tortillas for 7-8 mins until golden.
Step 5 — Make slaw
Meanwhile, thinly slice the cabbage with a sharp knife or mandoline. Pick the coriander leaves and finely chop the stems. Drain the onion, reserving 2 tsp pickling liquid in a large bowl. Stir 2 tsp extra virgin olive oil into the pickle liquid. Add the cabbage and coriander stems to the dressing, season with salt and pepper and toss to coat.
Step 6 — Get ready to serve
Carefully remove the taco shells from the oven rack and stand, flat-side down, on a board. Fill with the slaw, mince mixture and pickled onion. Crumble over the feta and scatter with the coriander leaves to serve.