Mary Berry's butternut squash lasagne recipe

Name: Mary Berry's butternut squash lasagne recipe
Prep time: 30 min
Cook time: 45 min
Total time: 1 h 15 min
Cuisine: British
Ingredients: 1 tbsp olive oil; 225g (8oz) butternut squash (peeled weight), chopped into small cubes; 1 red pepper, halved, deseeded, and diced; 1 onion, roughly chopped; 2 garlic cloves, crushed; 225g (8oz) chestnut mushrooms, sliced; 2 x 400g cans chopped tomatoes; 1 tbsp tomato purée; 2 tsp sugar; 1 tbsp freshly chopped thyme; salt and freshly ground black pepper; 100g (31⁄2oz) spinach, chopped; 6–8 sheets lasagne