A fast 30-minute sheet-pan taco with sticky, smoky barbecue tofu tucked into crisp, warm tortillas and finished with a cooling, tangy cabbage slaw. Balanced textures and big flavors make this a satisfying vegetarian or vegan weeknight dinner.
Place one large baking sheet in the oven and preheat to 425°F (218°C).
Make the slaw: In a medium bowl, whisk mayonnaise, apple cider vinegar, and grainy Dijon mustard. Add cabbage, red onion, and chives; toss to coat. Season with salt and pepper to taste and refrigerate.
Crumble the tofu into pea-size pieces using your fingers or a potato masher.
Heat a large nonstick skillet over medium heat. Add 1 tablespoon olive oil, then the crumbled tofu, fine sea salt, and black pepper. Cook, stirring infrequently, until the tofu is golden and crisp, 10 to 15 minutes.
Reduce heat to low. In a small bowl, whisk the cold water and cornstarch to make a slurry; pour over the tofu and toss until it thickens and bubbles. Turn off the heat.
Add the barbecue sauce and stir well to coat the tofu evenly.
Carefully remove the preheated baking sheet and lightly oil it with the remaining 1 tablespoon olive oil. Arrange the tortillas on the hot sheet.
Divide the saucy tofu evenly among the tortillas and press firmly to spread so it adheres to each tortilla.
Bake until the tortillas are slightly crisp and the edges begin to brown. Work quickly once out of the oven so the tortillas fold easily.
Top each tortilla with slaw and a drizzle of extra barbecue sauce, fold in half, and serve immediately.