Remove the thick stalks of the cabbage by holding the stems with one hand and using the other hand to strip away the leaves. Discard the stalks. Cook the leaves in a saucepan of boiling water for 15 minutes until just tender, then drain thoroughly.
Heat the oil in a large frying pan over a low heat. Add the garlic, crushed chillies and borlotti beans and cook for 5 minutes, then stir in the cooked cabbage. Season with salt and cook, stirring, for 6–8 minutes until the cabbage has completely wilted and absorbed the flavours. Serve immediately.