To prepare the casserole first allow the lamb to reach room temperature. Preheat your oven to 150 C.
In a dry saute pan, heat the cumin seeds until they begin to brown and pop. Transfer to a mortar and pestle and grind into a coarse powder. Set aside.
Add the sunflower oil to the hot saute pan and gently cook the onion for a few minutes, until it begins to soften.
Add the garlic, ground cumin and tomato puree and cook for a further minute or so.
Season the flour with smoked sea salt and freshly ground black pepper and toss in the lamb pieces until coated.
Add to the onions and brown for five minutes or so.
Add the lamb stock, bring to the boil and then transfer to a casserole dish.
Slow cook in the centre of the oven for 2.5 - 3 hours.
for the creamy herbed polenta
Melt the butter over a medium-high heat in a saucepan until it begins to bubble.
Add the spring onion and cook for two minutes, stirring occasionally.
Add the cream and bring to a simmer, but don't allow it to boil.
Add the herbs and set aside.
Meanwhile, bring the water and salt to a boil.
Gently add the polenta to the boiling salted water in a stream, stirring constantly. It will thicken fairly quickly.
Continue to stir, cooking for two minutes or so until it resembles thick porridge.
Remove from the heat, add the herbed cream mixture and the Parmesan cheese and stir well.
Serve immediately with the slow cooked Shetland lamb casserole on the side.
Notes
Any leftover polenta can be transferred to a dish to set. It will take the shape of whatever dish you put it in when it has cooled, and you can slice and fry it to reheat it. This will go well with any leftover casserole!