Heat the olive oil in a large frying pan over medium heat. Add the lamb mince and cook until browned. Remove and set aside.
In the same pan, sauté the onion, carrot, and celery for 5 minutes until softened.
Add the garlic, tomato paste, Worcestershire sauce and herbs. Cook for 2 minutes.
Return the lamb mince to the pan, stir, and pour in the red wine & beef stock. Simmer uncovered for 20 minutes until thickened. Season with salt and pepper.
While the filling simmers, boil the potatoes in a large saucepan of salted water for 15-20 minutes until tender. Drain and mash the potatoes with milk, butter, Dijon and a pinch of salt and pepper. Mix in cheddar if desired.
Preheat the oven to 200°C. Spoon the lamb filling into an ovenproof dish. Spread the mashed potato evenly over the top, creating peaks with a fork, sprinkle some cheddar cheese on top and a sprinkle of rosemary and thyme.
Place the dish on a baking tray to catch any drips and bake for 25-30 minutes until golden and bubbling.
Let it rest for 5 minutes before serving. Pair with buttered greens or steamed greens and bread and butter.
