Parmigiano Reggiano Roasted Vegetables and Chorizo Lasagne

1. Preheat the oven to 200°C/Fan oven 180°C/Gas Mark 6    
2. Put the onion, pepper, courgette and butternut squash into a large roasting tin and add the olive oil. Season and toss to coat.     
3. Roast for 20 minutes, then add the chorizo.     
4. Roast for 10 more minutes, until the vegetables are tender.    
5. Add the cherry tomatoes and pasta sauce to the roasted vegetables. Tip half the mixture into a large rectangular baking dish, measuring about 25 x 20cm.     
6. Arrange 3 lasagne sheets on top. Repeat the layers.    
7. Put the milk, butter and flour into a non-stick saucepan. Heat, stirring constantly with a small whisk until the sauce boils and thickens. Remove from the heat and add two-thirds of the Parmigiano Reggiano, stirring until melted.  Season.     
8. Pour evenly over the top of the lasagne and sprinkle the remaining Parmigiano Reggiano on top.     
9. Bake for 35-40 minutes, until golden brown.     
10. Serve, garnished with thyme sprigs or basil leaves. 

Cook’s tip: For a vegetarian version, simply omit the chorizo.