Heat a large pan on a medium heat . Drizzle with extravirgin olive oil and add onion, carrot, celery, garlic, bay leaves and most of the rosemary & thyme leaves.
Cook until the vegetables are soft, about 10 mins, stirring occasionally.
Add the minced lamb, season and stir fry over high heat until the meat has browned.
Fold the tomatoes in and cook for 5 mins, stirring occasionally.
Pour in the stock, season with salt and pepper and stir well, then bring to a boil.
Reduce to very low heat and slightly cover with a lid, then allow to simmer for about 50 mins.
While the lamb ragout cooks, make the potato mash.
Peel and cut the potatoes into quarters, and put them into a pot of boiling salted water.
Simmer for 10 mins or until cooked through.
Drain the potatoes and put them back into the pan. Add butter and salt & pepper to taste. Gently pour the milk and mash until you have fluffly and smooth texture.
Line a large baking dish or 4 individual baking pots with the lamb mixture.
Spoon the potato mash (or use a piping bag) evenly over the top of the meat. Sprinkle with butter flakes and the remaining herbs on top of the potatoes .
Bake in a preheated oven to 190ºC/375F for about 25 min, until golden and bubbling. Allow to cool a little and serve. Enjoy!