Heat the oil in a medium saucepan over a medium heat. Add the onion and carrots, and cook for 4-5 minutes or until softened. Add the lamb and, stirring regularly, cook for another 8-10 minutes or until browned.
Add the tomato paste, Worcestershire sauce and stir to combine. Pour in the stock and bring to a simmer. Reduce the heat to low and cover with a lid. Simmer for 35 minutes
While the lamb is cooking, place the potatoes in a large saucepan and cover with water. Place the pot over a medium heat and bring to the boil. Boil for 10 minutes or the potatoes become tender.
Drain into a colander and then return the potatoes to the pot. Add the butter, milk and season with salt and pepper. Mash together until you have a smooth mash
Divide the mince between 6 ovenproof pie dishes, and then top with mash. Transfer the pies into the oven to bake for 20-25 minutes or until the mash starts to turn golden
Remove the pies from the oven and allow to stand for 5 minutes before serving
Tips & Hints:
Try using beef mince instead of lamb to make these mini cottage pies!