Soak the lentils for a couple of hours.
Wash and boil the lentils until tender (about 20 minutes. Drain and set aside.
Meanwhile, finely chop the onions, garlic, celery and leek.
Chop the mushroom and chestnuts into small dices.
In a pot, heat the oil over medium heat. Add the bay leaves, onion, garlic, celery and leek and sauté until soft—about 5 minutes.
Now add in the mushrooms and sauté until soft.
Add in the chopped chestnuts and the boiled lentils.
Pour in the stock and add the salt and pepper. Bring to a quick boil and then reduce to a simmer and cook, stirring often.
Once the lentils are soft and most of the liquid has reduced off, stir in the harissa and mix well. Adjust the seasoning if required.
The lentil mix is ready when most of the liquid has been absorbed. Set aside to cool.
Remove the puff pastry roll from the fridge and bring it to room temperature.
Once the lentil mix has cooled completely, roll out the puff pastry (you will be using the whole packet) on a piece of parchment paper or a silicon baking mat. This will make it easier to move the wellington later.
Into the centre of the puff pastry sheet spoon in the wellington mix lengthwise. Leave about two inches on both ends to fold on over later. Shape the lentils mix like a log. We want it nice and tight.
Cut equal sized strips into the puff pastry, about ½ inch segments, either side of the log mix. Leave thicker strips at either end as shown in the photograph to enable proper sealing.
Mix the turmeric and plant based milk and brush the entire sheet with this.
Carefully bring the top end to cover the wellington mix and press down to seal the puff pastry. At this point you will have a double folded strip, cut it into the same size as the other strips. Repeat for the bottom end.
Now braid the pastry. Starting from the top sealed end, pull the strip for one side up and diagonally over the centre of the lentil log, then bring the other side and cross over the previous strip and press down. Repeat this process till you reach the end of the lentil log.
This is how the ends of the braided puff pastry should look
Brush the entire log with the plant milk and turmeric mix and refrigerate while you wait for the oven to preheat.
Preheat oven to 200ºC (fan assisted)
Place the wellington on a tray in the oven and cook for 20 to 25 minutes or until golden brown.
Remove from the oven and cool for at least five minutes before cutting and serving.