- Peel and dice 2.5 cups of Rooster potatoes.
- Boil the Rooster potatoes and sweet potatoes for 15-20 minutes, or until tender.
- Drain the potatoes, then mash with the milk using an electric whisk until smooth. Season with pepper.
- In a large pan over a medium heat, cook the ground meat until browned.
- Drain off any excess fat, then add the onion, celery and garlic and cook for another 3-4 minutes, stirring occasionally.
- Add the canned tomatoes, vegetable stock, Worcestershire sauce, herbs and mango chutney (optional).
- Bring to a boil, stirring until thickened. Reduce the heat, then cover and simmer for 20 minutes, stirring occasionally.
- Place the meat in an ovenproof dish.
- Spoon the mashed potato mixture over the top and texture the top with a fork.
- Pop into a preheated oven at 400°F for 20 minutes.