Heat the oil in a large pan and fry the bacon and mince in batches until browned. Add to the slow cooker.

Add the onions, carrots, celery, garlic, mushrooms, tomatoes, tomato purée, herbs, wine (if using), vinegar, sugar and seasoning to the slow cooker. Cover and cook on Low for 6-8 hours, then uncover, turn to High and cook for another hour until thick and saucy.

Serve with cooked spaghetti and grated or shaved parmesan. To cook this entire recipe on the hob, check out our big-batch bolognese recipe.