Preheat your oven to 450°F and line a baking sheet with parchment paper. Cut the cauliflower into bite-sized florets, making sure they are uniform for even cooking. This step ensures a perfectly crispy texture.
In a large bowl, mix the soy milk and apple cider vinegar and let it sit for a minute to curdle. Add flour, cornstarch, garlic powder, onion powder, and salt, whisking until smooth. Coat the cauliflower in this mixture so every floret is lightly covered.
Toss the battered cauliflower in panko breadcrumbs to form a crispy layer. Make sure each piece is evenly coated for maximum crunch after baking.
Arrange the coated cauliflower on the prepared baking sheet. Bake for 20-25 minutes, flipping halfway, until golden and crispy. The cauliflower should feel firm and slightly crunchy to the touch.
While the cauliflower bakes, mix vegan mayo, sweet chili sauce, Sriracha, and agave in a small bowl. Whisk until smooth. Adjust spice or sweetness to taste.
Once baked, toss the cauliflower in the prepared bang bang sauce. For extra crispiness, return the coated florets to the oven for another 5 minutes so the sauce sets slightly.