Pre-heat the oven to 180ºC. Place a sheet of baking parchment paper on the baking tray.
Rinse the spinach in a colander and shake well to remove the excess water. Place in a large saucepan, cover and put over a low heat for 6 - 8 minutes, stirring occasionally, until wilted.
Place a sieve over a bowl and tip the spinach into the sieve. Use a wooden spoon to press the spinach against the sieve to remove as much liquid as possible.
Discard the excess liquid, chop the spinach, then tip it into the bowl.
Add the ricotta, Parmesan, curry powder, garlic powder, salt and pepper to the spinach and stir to combine.
Take a single sheet of filo pastry and cut it in half lengthways to produce a 46 x 12 cm rectangle.
Spray the pastry rectangle with low calorie cooking spray, especially the edges.
Place a quarter of the filling mixture in the centre of one end of the pastry rectangle.
Fold one corner of the pastry diagonally over to enclose the filling. Press down the edges to seal.
Fold diagonally again, and press down the edges.
Repeat until you reach the end of the pastry rectangle and you have a triangular pastry parcel. Place the samosa seam side down on the prepared baking tray. Repeat this process to make the remaining 3 samosas.
Spray the samosas with low calorie cooking spray and place in the preheated oven for 20 minutes until golden, turning over once during cooking.
Remove from the oven, and allow to cool slightly before serving.