Add 1 cup (120 grams) flour into a large bowl, along with 1 tsp (4 grams) baking powder and ¼ tsp (1.5 grams) sea salt, whisk together, then make a well in the middle, crack in the egg and pour in the beer, whisk together until you get a creamy batter with no lumps
Heat a large fry pan with a medium to medium-high heat, add in the sunflower oil
Meanwhile, pat the cod fillets dry with paper towels, then season with sea salt & black pepper and cut each fillet into smaller handheld pieces
Coat the cod fillets in ½ cup (60 grams) flour and then in the beer batter, making sure to fully coat them through
Once the oil is nice and hot, about 8 to 10 minutes, add in the coated pieces of cod, making sure to shake off any excess batter and all in a single layer, fry for 2 to 3 minutes per side or until golden fried and the fish is cooked through, then transfer over a wire rack with paper towels underneath
To make the aioli, add in the mayonnaise into a bowl, finely grate in the garlic, finely grate the zest of half a lemon, add 1 tsp (5 ml) lemon juice and 1 tbsp (15 ml) extra virgin olive oil, season with sea salt & black pepper and whisk together
Transfer the aioli into a serving dish and the pieces of fried fish, garnish with lemon wedges and fresh parsley, serve at once, enjoy!