In a small bowl or mason jar, stir together the mayonnaise, apple cider vinegar, sugar (if using), and salt for the coleslaw dressing. Cover and refrigerate until ready to serve.
Preheat oven to 425ºF. Line a large baking sheet with parchment paper.
In a medium bowl, whisk together flour, cornstarch, baking powder, and salt for the batter. Whisk in the water until smooth. In a separate bowl, add the panko.
Holding the stem, dip each piece of broccoli into the batter to coat the floret, then into the panko. Place on the parchment-lined baking sheet.
Bake for 25 minutes, until crispy and golden.
Meanwhile in a small saucepan, bring the apple cider vinegar, brown sugar, gochujang, and salt for the sauce to a simmer. In a small bowl, whisk together the cornstarch and water to make a slurry. While stirring the sauce, pour in the slurry. Simmer until thickened, about 1-2 minutes.
Transfer the broccoli to a large bowl. Pour the sauce over top and toss to coat. In another large bowl, toss the shredded cabbage and carrot with as much creamy coleslaw dressing as desired. Serve with soft flour tortillas and garnish with thinly sliced green onion.
Notes
Storage: Store broccoli and coleslaw in separate airtight containers in the refrigerator for up to 3 days.