Remove the tough outer leaves from the savoy cabbage. Cut the head of cabbage into four, cutting from top to bottom. Cut out the core, then slice the cabbage crossways into fine shreds, about ¼in (5mm) thick.
Combine the butter and the water in a wide saucepan over a medium heat and allow the butter to melt. Toss in the shredded cabbage and season with salt and freshly ground black pepper. Cover with a lid and cook for two to three minutes, until the cabbage is just softened; do not overcook or allow the cabbage to burn. Taste immediately for seasoning, adding more salt and freshly ground black pepper if necessary, and serve.