Peel and boil potatoes until tender, drain.
Mash with butter, milk and egg until smooth.
While the potatoes are boiling, pre-heat oven 180*c.
Heat butter in pot, add onions, garlic and carrot and cook until soft.
Add mince, cook until brown.
Add tomato paste, beef stock and Worcestershire sauce.
In a separate cup add water and plain flour together and mix until smooth, then add the mixture to the pot. Give it a good crack of salt and pepper to taste.
Stir mixture until boils and thickens.
Pour beef mixture into dish.
Scoop spoonfuls of potato onto beef mixture.
Bake in oven for 20 minutes.