John Whaite’s vegan Wellington

1. Preheat the oven to 200ºC, gas mark 6. Put the diced squash on a roasting tray, drizzle with oil and season generously with salt. Toss to coat, then roast for 25-30 minutes, until the squash is cooked through and tender – a little charring on the corners is ideal, as that will impart some great flavour. Cool.

2. While the squash roasts, put the couscous for the filling into a large heatproof bowl and set to one side. Heat a generous frying pan over a medium heat and add the pecans. Toast, shaking about the pan frequently, until the nuts smell aromatic. Remove from the pan and place onto a chopping board, then return the pan to a high heat.

3. Add the olive oil, leeks and mushrooms and cook, stirring occasionally, for 15-20 minutes and reducing the heat if needed, until dry – once the sound of the pan becomes more of a dry crackle than a wet bubble and the vegetables have wilted and reduced in volume, they are ready. Add the garlic, herbs and nutmeg and stir through, then decant into a bowl to cool. If you’re short on time, spread the vegetables out in a large roasting tin so that they cool more quickly.

4. Return the pan to the heat and add the 150ml stock, bring to a boil, then pour it over the couscous. Cover and set aside for 6 minutes. Once the couscous has absorbed all the liquid and is swollen, fluff it up with a fork. Roughly chop the pecans and add them to the couscous, along with the mushroom mixture, the roasted squash, the remaining 4 tbsp stock and the Marsala. Season to taste with salt and white pepper, then allow to cool.

5. Divide the pastry in half and put each piece onto a sheet of baking parchment. Roll one half into a rectangle of about 15 x 30cm, then roll the second half a little larger. Take the filling mixture and pile into a compact sausage along the length of the pastry sheet. Leave about 5cm of pastry around the filling on the long edges, and 2.5cm at the ends. Lay the second, larger sheet of pastry over the filling and use your hands to compact it tightly around the mound of couscous mixture, expelling as much air as possible. Trim off the excess pastry, leaving a border of about 2cm. With floured fingers and thumbs, crimp to seal the edges of the pastry. Slide the Wellington, still on the baking parchment, onto a large baking tray. Mix 2 tbsp coconut oil with the turmeric to add golden colour, then brush it liberally over the pastry. Chill for 30 minutes before baking. (It can be kept covered in the fridge for up to 2 days, if you’re not cooking it straightaway.)

6. When you’re ready to cook the Wellington, preheat the oven to 200ºC, gas mark 6. Score a decorative pattern into the glazed Wellington using a sharp knife, then bake for 40-50 minutes, until puffed up and golden. When it comes out of the oven, brush with the final 1 tbsp coconut oil as a final glaze. For the relish, mix the ingredients together, then cover and store in the fridge (for up to 2 days) until ready to serve with the Wellington in thick slices.