1. Heat a dry skillet over medium heat and roast the poblano pepper, turning frequently, until the skin is charred. Place it in a covered bowl for 5 minutes, then peel, deseed, and slice.

2. In a bowl, whisk together the flour, cornstarch, paprika, garlic powder, onion powder, salt, and black pepper.

3. In a separate bowl, whisk the buttermilk and egg together.

4. Coat the shrimp in the flour mixture, dip into the buttermilk mixture, then coat with panko breadcrumbs.

5. Heat about 1 inch of vegetable oil in a skillet over medium-high heat. Fry the shrimp in batches until golden brown and crispy (about 2-3 minutes per side). Drain on paper towels.

6. In a small bowl, mix all the sauce ingredients until smooth.

7. Warm the tortillas in a dry skillet or microwave.

8. Assemble the tacos: place shredded cabbage on each tortilla, followed by crispy shrimp and roasted poblano slices.

9. Drizzle with the sauce, sprinkle with cilantro and cotija cheese, and serve with lime wedges.