Steam your fish for about 10 minutes.
Caramelized your onions in a pan for 5-7 minutes with a bit of olive oil.
Combine together flour, eggs, salt and pepper. Add your fish in small piece, parsley and the cooked onions.
Heat a large skillet with olive oil.
To get nicely shaped cakes, cook your batter in cookie cutter/cake rings directly in the pan (if you don't have cookie cutter, don't worry just cook directly in the pan).
Cook for about 4 minutes, remove the cookie cutter/cake ring, flip on the other side. Cook for an additional 2 to 3 minutes (until cooked).
Serve with homemade garlic mayonnaise and fresh lemon to squeeze on your fish cake.