Fish Sandwich with Chile-Lime Mayo

• 1/4 cup mayonnaise 
• 2 tablespoons freshly squeezed lime juice 
• 1 tablespoon chile powder 
• 1 teaspoon minced garlic 
• Salt and freshly ground black pepper 
• 1/4 cup neutral oil, like grapeseed or corn, plus more as needed
• Four 4-ounce fillets of firm white fish, like cod, halibut, or catfish, salmon, or mahi-mahi
• 1/4 cup of all-purpose flour 
• 1 egg, beaten with 2 tablespoons of water 
• 3/4 cup of bread crumbs, preferably fresh 
• 4 rolls or 8 slices bread, toasted if you like 
• 8 slices ripe tomato 
• 2 cups shredded Napa cabbage or iceberg lettuce 
• 1/4 cup chopped fresh cilantro leaves (optional)

Mix together the mayonnaise, lime juice, chile powder, garlic, and some salt and pepper; taste, adjust the seasoning, and set aside. 

Put the oil in a large skillet over medium-high heat. Sprinkle the fish with salt and pepper, then dredge both sides of the fillets in the flour; dip in the egg, and coat in the bread crumbs. When the oil is hot, add the fillets and cook until golden brown on both sides, about 8 minutes total. 

To assemble the sandwiches, smear the rolls with the chile-lime mayo, add the fillets (cut in half to fit on the bun as necessary), and top with tomato slices, cabbage, and cilantro if you’re using it. Serve immediately.