Boil the potatoes in lightly salted water till tender. Peel the skin and drain excess water.

Return the potatoes to the saucepan, break down into small pieces with the ladle, add two-thirds of the butter and mash well till almost smooth. Next whisk in the milk and season with salt and pepper. Keep aside.

To prepare the lamb mixture, heat oil in a heavy pan, add the onions, carrot, celery and pumpkin for about 8 minutes on medium heat.

Add the garlic and garam masala and cook for a further 2 minutes.

Add the lamb mince and stir it in on high heat for about 2-3 minutes. Reduce to medium heat and cook till the lamb is almost done.

Add vinegar and cook till the liquid in the pan has reduced completely.

Next, stir in the remaining butter; and slowly add flour while stirring continuously.

Add the beef stock and stir well scraping all the browned bits off the bottom of the pan.

If the mixture feels too dry, add a little water. Season with salt and pepper.

While this is cooking, preheat the oven to 180°C (fan-forced).

Once the lamb has cooked, transfer it to an over proof dish and spoon the mashed potatoes on top; spread to cover the pan. Drizzle the surface slightly with oil, season with salt and pepper.

Bake uncovered for 30 minutes or till the potato mash has nicely browned to form a crust.

Cool slightly before serving.