Heat a grill to a medium heat.
Rub the steaks with the oil, salt and pepper and grill, flipping every 30 seconds for 2-3 minutes, depending how well you like it.
Take off the heat and leave to rest for 2 minutes before plating.
Peel and dice the shallots, pick rosemary leaves from the stalks and finely chop.
Sweat the shallots with the butter in a small sauce pan until soft and translucent.
Add the rosemary, red wine and port and reduce to 1/3.
Add the veal stock, Worcestershire and the jelly, bring to the boil, reduce to a simmer until desired consistency is achieved.
Season with salt and pepper to taste.
Dice the cabbage and peel and dice the onion.
Cut potatoes into quarters and put in a pan covered by cold salted water, bring to the boil and reduce to a simmer for 20-25 minutes or until tender.
Put the onion and cabbage in a pan with a lid and sweat, over a medium heat until softened, stirring occasionally as not to colour.
Add the milk to the potatoes and crush slightly before adding to the onion and cabbage mixture.
This should still be quite lumpy and textured, not smooth.
Season with salt and pepper.
Serve in a bowl or on a plate and top with a knob of the butter
«The leg steak is a relatively cheaper cut of lamb but when cooked properly is delicious and tender. The colcannon is classically made with left over potatoes and cabbage from a Sunday Roast and is also lovely with the addition of bacon. »