Slow-baked vegetable ‘lasagne’

Method

1. For the white sauce, put the milk in a medium saucepan, add the bay leaves and thyme, bring to a simmer, then set aside to infuse for 10-15 minutes.
2. Meanwhile, melt the 30g butter in a medium saucepan over a low-medium heat. Once foaming, quickly stir in the flour, then cook, whisking, for 2-3 minutes. Gradually add the infused milk, whisking all the time. Once all the milk has been incorporated, simmer gently for 10 minutes. Season to taste, then discard the herbs and keep the sauce warm until needed.
3. Heat the oven to 180°C/160°C fan/gas 4. Layer the vegetables in the prepared baking dish, alternating the different kinds of vegetable evenly, making sure they get right into the corners of the dish and seasoning with salt and pepper as you go. Pour over the white sauce to fully cover the vegetables, transfer to the oven and bake for 40-45 minutes or until the vegetables are tender.
4. Meanwhile, make the crumble topping. Melt half the 50g butter in a small pan over a low-medium heat until bubbling, then stir in the shallot and cook for 5 minutes or until softened and lightly golden. Transfer to the bowl of a food processor with the remaining butter, the bread, herbs and nuts. Season with salt and pepper, then whizz to a rough crumble.
5. Sprinkle the crumble mixture over the baked vegetables, then return to the oven for 20 minutes or until the crumble topping is golden brown.