Heat a medium size fry pan with a medium heat and add in the sunflower oil

In the meantime, pat the cod fillets dry with paper towels, then season with sea salt & black pepper

Add the flour into a bowl, along with the sweet smoked paprika, garlic powder and season with sea salt & black pepper, mix together, crack the eggs into a separate bowl, season with sea salt & black pepper and whisk together, add the panko bread crumbs into a third separate bowl

Coat each cod fillet, first in the flour mixture, then in the egg wash and finally into the panko bread crumbs, making to fully coat the fillets at each stage

Add the coated fish fillets into the hot fry pan, fry for 3 to 4 minutes per side or until golden fried and fully cooked through, then transfer over a wire rack with paper towels underneath, let them rest for 5 minutes

In the meantime, lightly toast the brioche buns, thinly slice the red onion, reserve the shredded lettuce and make the aioli, add the mayonnaise into a bowl, finely grate in the garlic, add in the chopped parsley, lemon juice, olive oil and season with sea salt & black pepper, whisk together until you get a creamy sauce

To assemble the sandwiches, add a dollop of the aioli over the bottom slice of the sandwich, top it off with a fried fish fillet, then add in some sliced red onion and shredded lettuce, add another dollop of the aioli on the top slice of the sandwich and place over the sandwich, serve at once, enjoy!