Cut the lamb meat into small bite-size pieces.
Place a non-stick skillet or Dutch oven over medium heat, add oil, and once hot, brown the meat on all sides. Once nicely browned set aside.
Add the onions to the same pan. Cook stirring for 5-6 minutes. Add garlic and cook for another 30 seconds.
Add the lamb, onions, and all remaining ingredients, excluding the mashed potatoes and cheese, into a 6-quart slow cooker. Season with salt and pepper, and stir well.
Wipe down the sides of the slow cooker, then spread the mashed potatoes on top of the beef mixture all the way to the edges of the crock to seal in the ingredients below.
Place a long piece of paper towel over the slow cooker to absorb the steam, and cover with the lid.
Cook on high for 4-5 hours, or low for 8-10 hours.
When ready to serve, sprinkle the cheese on top of the potatoes, cover, and cook for another 15 minutes, until the cheese is melted.
Serve hot and garnish with parsley.
