300 g (10 oz) butternut squash, peeled, deseeded and chopped
200 g (7 oz) mushrooms, halved
60 g (2 1/4 oz) butter
2 tablespoons plain flour
400 ml (14 fl oz) milk
2 teaspoons wholegrain mustard
100 g (3 1/2 oz) Cheddar cheese, grated
Steam the vegetables in a steamer for 8–10 minutes until tender.
Meanwhile, melt the butter in a small saucepan, then stir in the flour to make a roux. Cook for 1–2 minutes, then gradually whisk in the milk, and cook, stirring continuously, until the sauce is thick and smooth. Stir in the mustard and half the grated cheese.
Transfer the vegetables to an ovenproof dish, pour over the sauce and sprinkle with the remaining cheese. Cook under a preheated hot grill for 5–6 minutes until bubbling and golden.