Prepare the batter: Mix egg, flour, and water until a slightly thick consistency is achieved.

Finely chop onions and place in a bowl.

Combine ground meat, chopped onions, egg, mayonnaise, salt, pepper, and nutmeg (if using) in the bowl.

Mix well until the mixture becomes sticky.

Add panko breadcrumbs to the mixture.

Mix thoroughly with your hands, adding more panko if needed.

Form the mixture into equal-sized balls.

Place panko breadcrumbs in a bowl.

Coat each meatball evenly with the batter from step 1.

Transfer the batter-coated patty into the bowl of panko and cover it completely with breadcrumbs.

Gently flatten each breadcrumb-coated meatball into a patty shape.

Heat oil to 180C (350F) in a deep fryer or large pot.

Carefully place the patties into the hot oil and deep fry until golden brown on one side.

Flip the patties over and lower the oil temperature to 160C (320F).

Continue to cook thoroughly until the patties are cooked through.

Raise the oil temperature back to 180C (350F) for a crispy finish.

Remove the patties from the oil and drain on paper towels.

Serve hot.