Make gushes on the surface of the meat to allow the marinade to penetrate through the meat.
Place the meat between two pieces of parchment (baking) paper, top with potatoes, onions, and paprika, then set aside.
Blend olive oil, lemon juice, lemon rind, salt, black pepper, and paprika to make the marinade.
To the marinade, add dried oregano, chicken or lamb stock, and thyme. Stir to combine.
Pour the marinade on top of the lamb and veggies. Massage it through the meat.
Top with tomatoes, bay leaves and rosemary.
Transfer the meat to your slow cooker and cover it tightly with two pieces of parchment paper.
Slow cook on low for 10-12 hours or on high for 5-6 hours.
Once cooked, remove the lid and carefully open the parchment paper.
Serve with some tzatziki or as preferred.