For the sauce, simmer the cashew nuts in a pot of just-boiled water for fi ve minutes until soft. Drain and rinse.
For the veg, cut the broccoli and sweet potato into small bite-size pieces. Add the sweet potato to a large pan along with one teaspoon of oil and a generous pinch of salt, cook on medium heat for 2-3 minutes.
Add the broccoli and mix well, then add two tablespoons of water and cover the pan with a tightly fitting lid, this will help trap the steam and cook your veg quicker. Cook for 4-5 minutes until the broccoli is just cooked but not too soft.
For the sauce, add the rinsed, soaked cashew nuts into the blender along with the water, garlic powder, lemon juice and salt. Blend until smooth.
Mix the sauce through the cooked veg while still warm, add to the ovenproof dish and smooth out to an even layer.
For the filo pastry topping, using scissors, trim the pastry sheets to fit your pie dish.
Take one sheet of pastry at a time, brush generously with olive oil and transfer to cover the top of the pie.
Repeat until all seven sheets have been used, tucking the pastry in around the sides.
Bake in the oven for 10 minutes until the pastry is golden brown.
Remove from the oven and serve with your favourite salad.