Slow-cooked chunky beef lasagne

Name: Slow-cooked chunky beef lasagne
Prep time: 45 min
Cook time: 3 h
Total time: 3 h 45 min
Cuisine: European, Italian, Mediterranean
Ingredients: 2 tbsp olive oil; 400g beef shin diced; 1 onion finely chopped; 1 large carrot finely chopped; 1 celery stick finely chopped; 160g smoked pancetta diced; 150ml red wine; 400g can chopped tomatoes; 3 tbsp tomato purée; 300ml beef stock; 1 bay leaf; 2 rosemary sprigs; 2 tsp sugar; 500g dried lasagne sheets; 30g parmesan grated; 150g mozzarella grated; green salad to serve (optional); 100g butter; 100g plain flour; 1 litre whole milk; 50g parmesan grated; grating of nutmeg