To a deep dutch oven, add the oil, filling it halfway. Heat the oil to 375 degrees F.
While your oil is heating up, prepare your fish. In a large bowl, whisk together 1 1/2 cups flour, baking powder, beer, garlic powder, salt, black pepper and cayenne pepper until smooth. Set aside.
In a shallow bowl, add the remaining 1 cup of flour.
Taking each piece of cod, dredge in the flour, shaking to release any excess. Then add the fish to the batter, making sure to fully coat each piece and shaking to get rid of any excess. Immediately transfer the fish to the hot oil. Fry the fish for about 5-6 minutes, flipping once, until brown and crispy. Work in batches, so that you do not overcrowd the pan. I fried about 5-6 pieces at once.
Transfer the fish to a paper towel-lined plate, or place in a low oven to keep warm until you are ready to serve.
Assemble your tacos by layering sweet potato fries, fried cod and spicy tartar sauce on 8 flour tortillas. Sprinkle with fresh parsley and drizzle with fresh lemon juice.
Enjoy!