I am a little home sick these day so I make some home everyday food to try and make it easier. In Korea I have to use ground beef at home I would use lamb.
I sauteed carrots, mushrooms, onions, celery in butter. I add the beef and brown it . Then I add a beef stock cube (you can use Sogogi Dashida (소고기 다시다)) Some thyme, Fresh rosemary and a little sage . After about 10 minutes on medium heat I add a little corn starch to thicken it (at home I would use some bisto I cant help it. Its an Irish thing. More about Bisto here). For the potatoes I boil them first them mash them to make great mash I use cream ,butter and just a little salt. On a usual night I use milk instead of cream.
Then You should put the potatoes on the meat and put in a preheated oven at 210c. Dab the potatoes with a fork to make nice and crunchy .
cook for 20 mins
(other things you may use Worcestershire sauce, red wine if your really not traditional garlic)