Preheat the oven to 180°C (fan)/200°C/gas mark 6.
Peel and dice the sweet potatoes, drizzle with olive oil and roast for 30-40 minutes until soft. Stir occasionally.
Next prepare the beetroots. Heat the olive oil in a large non-stick pan with a lid. Add the onion, stir, and cook over a low-medium heat for 10 minutes until soft. Add the crushed garlic, stir and cook for a further minute or two.
Next add the grated beetroot, potato slices, almond milk and thyme. Stir well, reduce the heat to low, cover and simmer for 15 minutes or until the potatoes are cooked through. Stir occasionally.
For the chard, separate the leaves and the stalks. Finely chop the stalks and shred the leaves. Heat the olive oil in a frying pan or wok, add the stalks and fry for 5-10 minutes until softened. Add the chard leaves, lemon juice and parsley and cook for a further 5-10 minutes until wilted.
Finally make the beans. Heat the olive oil in a small pan, add the beans, garlic, lemon zest and water and warm through. As the beans start to soften mash them together. You may need to add a little more water but don't worry if they seem dry as they'll absorb liquid from the beets once they're in the pie together.
Now it's time to assemble your pie. Brush a pie dish with oil and spread a sheet of filo pastry over the base. Brush again with oil and cover with a further two sheets, brushing each sheet with oil.
To layer the pie first start with the sweet potatoes, then add the butter beans, the chard and finally the beetroot mixture to the top.
Draw in any filo pastry that is hanging over the sides and cover the top of the pie with 2-3 sheets of pastry, brushing each with oil as you go. Tuck the edges in to the side of the pie dish.
Brush the top with a little more oil and bake in the oven for 20-25 minutes, until golden brown.
Serve with a green salad.