Fry the beef mince in batches until brown all over. (You shouldn't need any oil as fat will be released from the mince.) As it cooks, spoon it out into a dish.
In the same pan, in the fat left in the pan, fry off the onions, carrots, celery, garlic and thyme gently for about 10 minutes until starting to soften.
Add the meat back into the pan with the vegetables and stir in the flour and mix well so it's disbursed through.
Pour in the red wine (if using) and allow to bubble away for 5 minutes.
Add in the beef stock, Worcestershire sauce, tomato puree and plenty of salt and pepper. Put the lid on and cook gently over a low heat for 30 minutes, stirring occasionally.
Preheat the oven to 180℃/350F fan, 200℃/400F or Gas Mark 6.
Meanwhile, boil the sweet potatoes and white potatoes in a pan of boiling water for about 20 minutes until soft and tender.
Drain and mash well.
When the mince is cooked, transfer to one large or two smaller shallow dishes. Top with the mashed potatoes, sprinkle on the cheese.
Bake in the oven for about 20 minutes or until the cheese is bubbling.
Did you make this recipe? Click here to let us know how it went and give it a ⭐️ rating! Your feedback helps us to make more recipes you really want.