Butternut squash roulade

Method

1. Heat the oven to 200°C/180°C fan/gas 6. Put the squash in a roasting tin, drizzle with olive oil and season with salt and pepper. Roast for 20 minutes, then add the whole garlic with the onion and roast for 20-25 minutes until all the vegetables are tender. Leave to cool, put the veg in a food processor or blender (squeeze the garlic from its skin first and discard the skins) and whizz to a purée. Scrape into a bowl (no need to wash the blender). Set aside.
2. Melt the butter in a heavy-based saucepan over a low heat and cook the crushed garlic for 2 minutes. Stir in the flour with a wooden spoon, then cook for 3 minutes or until it’s a pale gold colour. Gradually add the milk, stirring constantly, to make a smooth sauce. Simmer briskly for 2-3 minutes, stirring regularly, until thick and velvety, then add the grated hard cheese and stir to melt. Cool.
3. Pour the cooled sauce into the food processor. Add half the dill, most of the parsley (reserve a handful) and the egg yolks, one at a time, whizzing after each addition to combine. Scrape the mixture into a clean bowl.
4. Put the egg whites in a large, clean dry mixing bowl and whisk with an electric hand mixer to form soft peaks. Using a metal spoon, fold the whites gently into the sauce mixture. Quickly pour the roulade mix into the prepared swiss roll tin, then bake for 15-20 minutes until puffed up but with a slight wobble. Leave to cool in the tin for 5 minutes. Loosen the edges with a knife and invert onto a large sheet of baking paper. Gently peel away the paper from the roulade.
5. Put the goat’s cheese in a mixing bowl with the remaining dill, the lemon zest, lemon juice and soured cream, then season and mix. Spread the roulade with the mixture, then spread the reserved squash purée over the top. Allow to cool completely.
6. Working from a short side, use the baking paper underneath to roll the roulade, gently but tightly, into a cylinder, then put it seam-side down onto a serving plate or tray and chill for two hours (see Make Ahead).
7. Meanwhile, toast the chopped walnuts in a dry pan until golden, then add a drizzle of olive oil and the remaining handful of parsley and cook until the parsley is crisp. Season well. Take the roulade out of the fridge around 20 minutes before serving to bring it back to room temperature. Serve scattered with the walnuts and parsley.