Cabbie Claw is a Scottish dish of cod served in white sauce with chopped egg white in it.
To make it, the cod is cleaned, then rubbed with salt inside and out, then hung outside to dry in the wind for 24 to 48 hours.
The cod is then simmered for about half an hour in enough water to cover it, flavoured with horseradish and parsley.
You remove the fish from the water (saving the cooking water.) The fish is skinned and boned, and the flesh flaked into large pieces, and kept warm.
To make the white sauce, you make a roux, then add milk and some of the water that the fish was simmered in (or just milk, or just the water), and stir until thickened. When thickened, chopped cooked egg whites are stirred in.
To serve, you put the fish pieces on a platter with a ring of mashed potato around it. Pour the sauce over the fish, and garnish with chopped egg yolk, chopped parsley, and cayenne pepper.
The cayenne pepper garnish would be clearly be a modern addition.
Modern recipes just start with cod fillets from the store.
Traditionally, other white fish such as haddock, whiting, etc, could be used.
Also spelt “Cabelew.” Presumed to be a corruption of “cabillaud”, the French name for cod.