Combine the chopped cod, egg, masala powder, salt, and laksa leaves in a food processor.
Pulse into a rough farce.
Combine fish mince mixture and flour in a bowl.
Form mixture into patties and allow to set in the freezer for 10 minutes.
Put patties into a sous vide bag with some olive oil.
Cook for 30 minutes at 130°F.
Sear the patties for 45 seconds each side in a non-stick skillet.
Combine all ingredients for the aioli in a bowl.
Assemble the burgers.
Spread aioli on both halves of each burger bun, layer lettuce, and fish patties.
Notes
Any lean fish could be worked into this patty. Mahi-mahi, snapper, bass. . . even other seafood such as prawns, crabmeat, and lobster.
Shape the patties, handling them with a very light touch. Pressing too hard on them will toughen them up as they cook. Try to shape them at least an inch thick and just a bit bigger than your bun in diameter. They'll shrink and fit perfectly into those buns as they cook. Give them a few minutes in the freezer to set a bit so they'll keep their shape as you get them in the sous vide bag.
Bag the patties up a bit loosely. Doing so via the water displacement technique would be perfect. Sealing them in really vacuum-tight would press too hard on the meat and consequently toughen the burgers.
Some chopped cilantro and chili flakes would be excellent additions to the aioli.