To make the meat filling, heat the butter and olive oil in a large pan.

Add the chopped garlic and red chilly flakes and sauté.

Add the chopped white onion and sauté till translucent.

Add the minced lamb (preferably lean mince) and break it up in the pan. Cook till evenly browned.

Add in the mushrooms, peas, carrots and celery. Mix well to combine. The veggies will release their liquids into the pan. Cook them off over medium heat.

Add the ketchup and tomato paste and mix well.

Add the dried herbs, salt and enough pepper to season well (don't skimp on the pepper!).

Place the hot filling in the base of an oven proof dish (large enough to hold all of it in) and set aside to cool.

Meanwhile, preheat the oven to 180 °C.

While the oven is pre-heating, mash the potatoes with the milk, butter, garlic salt, pepper and onion powder. You can add more milk if you like. Mash it well till it's soft and velvety.

The meat filling should now be relatively cool. You might notice that the filling will have almost set into a firm, solid layer. This is good.

Pile the mash over the filling and smooth it over till the edges of the dish are completely sealed.

Make a decorative pattern of some sort over the mash (I made fish scales).

Bake in the pre-heated oven for around 15 minutes. Then set the oven to broil and bake for a further 5 - 7 minutes, till the top is nice and golden brown.

Let rest for 5 minutes before serving.