Place the vegetables in a bowl and mix them together well with the olive oil.
Spread the vegetables out on a baking tray and roast them in the oven for 20 – 25 minutes until softened.
Season the roasted vegetables.
Take one sheet of filo pastry, spray it with the olive oil cooking spray and fold it in half lengthways, then spray it again so you have a long strip (2 layers of filo pastry). *
Crumble a little of the feta cheese and about 2 tbsp. of the roasted veg mixture at the right end of the strip, leaving a 2cm / 1-inch border. Fold a corner over, diagonally to the left, making an enclosed triangle. Fold again, moving all the way along until the end of the strip. Spray the outside. Place the triangular filo parcel on a cleaned greased baking tray.
Repeat the process with the other 7 sheets
Bake in the centre of the oven for about 20 minutes, turning the triangles over halfway through.
Remove from oven and allow to cool a little before serving.