Preheat the oven to 180˚C / gas mark 4 and boil the kettle.
Finely dice the carrot and onion.
Heat an oven proof casserole dish on a medium heat and fry off the carrot & onion for 3-4 minutes in the olive oil. If you don’t have an oven proof dish that will work on your hob, just use a saucepan and then transfer the mixture into a casserole dish before putting in the oven.
Once soft, remove the carrot and onion from the pan and set aside.
Add the lamb mince to the pan, breaking it up with a wooden spoon and pan fry for around 5-6 minutes until browned.
Once the lamb is browned, drain the fat from the pan into a bowl.
Add the carrot and onion mixture back into the pan with the lamb, then add the peas to the pan.
Stir in the flour, make up the stock then add to the pan along with the bay leaf. Season with black pepper.
Stir again and let the mixture cook out for a few minutes allowing the sauce to thicken.
Meanwhile, peel and slice the sweet potatoes into rounds about ½cm thick.
If you are using a different pan, transfer the mixture to your oven proof dish.
Arrange the sweet potatoes over the top of the mixture in a fan pattern
Sprinkle some dried thyme over the top of the sweet potatoes and bake in the oven for 40-45 minutes until bubbling and the potatoes have crisped up.