Creamy Celeriac and Sprout Puree

Preheat the oven to 350F/180C/Gas 4. Bring two pans of water to the boil and cook the sprouts in one for about 8 minutes until tender, then drain. Cook the celeriac in the other pan for 15-20 minutes until tender. Drain. While the vegetables are cooking, melt the butter in a small pan, add the flour and cook for 1 minute. Gradually stir in the milk and bring to the boil, stirring, until you have a smooth, thick sauce. Season. Place the drained vegetables in a food processor or blender with the white sauce and process until smooth. Add the egg yolk and cream and process again until combined. Check seasoning. Pour the vegetable mixture into a buttered baking dish and sprinkle with the breadcrumbs and Parmesan. Bake for 20-25 minutes until puffy and golden. Serve immediately. Servings: 4