Start with the mash. Place the peeled, quartered potatoes in a large pot and cover with cold water. Season generously with salt and bring to the boil. Cook until knife-tender, then drain in a colander and allow the steam to evaporate for a minute or two.
Pass through a potato ricer or mash well. Stir through the warm milk, butter, egg yolk, nutmeg, Dijon and cheese if using. Season well and set aside.
Preheat the oven to 180°C (350°F).
Heat the olive oil in a medium-to-large skillet over medium heat. Add the onion, carrot and celery and cook for about 8 minutes until softened, stirring regularly.
Add the spices and dried herbs and cook for a minute until fragrant. Add the tomato paste and garlic and cook for another minute or two. Add the chopped pepper and fry for a further minute.
Add the beef mince, breaking it up well, and fry until cooked through. Season generously with salt.
Add the bay leaves and stock and simmer for a few minutes. Stir through the chutney, taste, and adjust the seasoning. The mince should still be fairly juicy at this stage. Remove the bay leaves.
Transfer the mince to a casserole dish if not already using an ovenproof skillet. Spread the mashed potato evenly over the top and make a few swirls across the surface. Brush with the melted butter if using.
Bake for 30 minutes or until the top is golden to your liking.
Serve with extra chutney on the side.