Mary Berry's butternut squash lasagne recipe

Mary Berry's butternut squash lasagne recipe is a hearty, vegetarian main for the colder months.

Mary Berry is not just queen of cakes, her butternut squash lasagne is a delicious dish that makes great use of this buttery, autumnal vegetable. This recipe shows you how to make a rich, white sauce, infused with mustard, from scratch. If you can, prepare the dish the day before, so the lasagne sheets have time to soften in the sauce. Serve with salad and crusty bread.

Ingredients

• 1 tbsp olive oil
• 225g (8oz) butternut squash (peeled weight), chopped into small
• 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

For the white sauce

• 75g (21⁄2oz) butter
• 75g (21⁄2oz) plain flour
• 900ml (11⁄2 pints) hot milk
• 2 tsp Dijon mustard
• 100g (31⁄2oz) Gruyère cheese, grated
• 250g (9oz) mozzarella, chopped into small cubes

Method

1. Heat the oil in a large deep frying pan. Add the squash, pepper, onion, and garlic and fry over a moderate heat for 4–5 minutes or until the onion is starting to soften. Add the mushrooms, tomatoes, tomato purée, sugar, thyme, and some salt and freshly ground black pepper. Cover with a lid and simmer over a low heat for 20–30 minutes or until the vegetables are tender. Add the spinach and toss together until just wilted.
2. Meanwhile, make the white sauce. Melt the butter in a saucepan, add the flour, and stir over the heat for 1 minute. Slowly whisk in the hot milk until the sauce is smooth and thick. Season with salt and freshly ground black pepper, then stir in the mustard and half the Gruyère.
3. Spoon one-third of the tomato sauce over the base of the ovenproof dish, then spoon one-third of the white sauce on top. Arrange a single layer of lasagne over the white sauce and scatter over half the mozzarella. Spoon half the remaining tomato sauce on top, followed by half the remaining white sauce. Arrange another layer of lasagne on top and scatter over the remaining mozzarella. Spread the rest of the tomato sauce on top, followed by the rest of the white sauce, then sprinkle with the remaining Gruyère.
4. Transfer to the fridge for at least 6 hours or overnight so the lasagne starts to soften.
5. To serve, preheat the oven to 200˚C (180˚C fan/400˚F/Gas 6), then bake the lasagne for 45 minutes or until golden brown and bubbling around the edges.

Top tip for making Mary Berry's butternut squash lasagne

The lasagne can be made up to the end of step three, up to two days ahead. You can then freeze it for up to two months.