Prep time: 40 minutes
Cooking time: 1 hour 20 minutes plus 1 hour chill time
Preheat the oven to 190°C. Place the beetroot, squash, onion and garlic in a roasting tin with 2 tbsp of olive oil. Scatter over the sumac and thyme and some salt and pepper and toss until the vegetables are well coated.
Roast for 45 minutes or until the vegetable are tender. Remove the garlic cloves and squeeze out the insides. Add half back to the tray along with the lentils and chopped chestnuts. Mix thoroughly then leave to cool completely.
While the mixture is cooling, make the pesto. Place the rest of the garlic, lemon juice, watercress, olive oil and pine nuts into a food processor and blend into a thick pesto. Taste and adjust seasoning.
Place the sheets of puff pastry onto a lightly floured surface. Cut each sheet into three to create six sections for the six individual wellingtons. Spread the pesto on one half of each piece of pastry, leaving the other half free of filling so that you can fold it over the top later. Ensure that you leave a gap all around the edge of the pastry so that you can stick the edges together.
Divide the roasted veg mix between the six pieces, placing on top of the pesto. Brush all the way round the edges of each piece of pastry with almond milk, then fold the plain half of the pastry over the filling. Use a fork to crimp around the edges and seal in the filling, ensuring that no air is trapped inside. Once the edges are crimped, use a sharp knife to trim them back into a neat rectangle shape. Poke a small hole in the top of each wellington to allow any steam to escape during cooking.
Place the six individual wellingtons on a baking tray lined with greaseproof paper, cover with clingfilm and chill for at least one hour or preferably overnight.
Preheat the oven to 190°C. Brush the top of each wellington with a little more almond milk and sprinkle with sumac. Bake for 30 minutes or until piping hot and crisp and golden on the outside. Scatter over the some thyme leaves and sea salt and serve.
2 raw beetroot, peeled and cut into 1cm chunks
100g whole cooked chestnuts, roughly chopped
½ a butternut squash, peeled and cut into 1cm chunks
1 red onion cut into wedges
4 cloves garlic unpeeled
6 tbsp olive oil
1 tbsp picked thyme leaves, plus extra to finish
1 tbsp sumac, plus extra to finish
250g cooked puy lentils
2 x 320g ready-rolled puff pastry (suitable for vegans)
2 tbsp almond milk
For the pesto:
50g pine nuts, lightly toasted
Juice of half a lemon