Add potatoes to a medium saucepan, filled with cold water, on high heat.
Bring to boil, then simmer for 15 minutes or until potatoes are tender.
Heat olive oil In a Dutch oven or large baking dish over medium high heat.
Add beef mince, season with salt and pepper, and cook for about 5 minutes stirring occasionally until browned.
Add onion, carrot & celery and cook fro a further 3 minutes.
Add garlic, plain flour, paprika, thyme & rosemary, stir to mix through and cook for a further 2 minutes.
Add beef stock and stir to mix through. Reduce heat and simmer for 20 minutes until mixture thickens slightly. Stir occasionally.
Remove from heat, and smooth mixture in readiness for potato mash.
Pre-heat a fan forced oven to 150°C (300°F).
Drain potatoes and add butter, milk, parmesan & season with salt and pepper. Using a potato masher or wooden spoon, blend all ingredients until a smooth mash mixture is produced.
Spoon mash over the top of the beef mixture in the dutch oven and spread evenly.
Sprinkle the mash with extra grated parmesan and garnish with sprigs of thyme.
Place in oven and bake for 40 minutes, until parmesan melts and mash is golden.
Remove from oven & let rest for 5 minutes before serving with your favorite vegetables or salad.