- Put the lamb mince, seasoning, onion and mustard into a large bowl. Mix together thoroughly.
- Divide the mixture into four and shape into burgers. Line the grill pan with foil and place burgers under a pre-heated grill and cook for about 12 minutes until golden and cooked through.
- Make the Welsh Rarebit: Mix together the mustard, cheese and beer.
- During the last 1-2 minutes of cooking place the rarebit in a mound on top of the burgers and allow to melt and ooze over the burger. Collect any juices in the bottom of the grill pan and spoon over the burgers.
- Serve with chunky fries and seasonal salad or slaw. A rare treat. Or not. It’s so easy to cook; you could have it again tomorrow if you wanted.