Firstly pre-heat your oven to 200C (390F)
Now to a large pan, add a drizzle of olive oil, 200g chopped mushroom, 150g chopped chestnuts and 2 tbsp Tamari and cook together for a few minutes until the mushrooms soften and brown off
Now add the drained lentils (make sure no excess liquid), 2 crushed garlic, 2 tbsp gravy powder, 1 tbsp tomato puree, 2 tsp dijon mustard, large sprig of rosemary and thyme finely chopped and mix
Cook together for a couple minutes, then take off the heat and allow to cool for 5-10 minutes
Meanwhile place your first pastry sheet onto a baking tray then spoon on the lentil mix making sure to not go right to the edges, give it some height I aim for 2 inches and keep it compact
Once the shape is formed (see the step by step photo in the photos above) place the next pastry sheet on top and press tightly round the edges
Cut off any excess pastry (save for shapes) then press round the edges with a fork before slicing a few lines into the top to release steam, now lightly glaze the top with olive oil
Place in the oven at 200C (390F) for 20 minutes until lightly golden, allow to sit for 5 minutes before slicing (make sure to cut carefully with a cerated knife)