Preheat oven to 200°C. Lightly spray four non-stick pie dishes with olive oil. Set aside.
Place sunflower seeds and pepitas onto a small baking tray and toast in the oven for 4-5 minutes or until golden. Set aside.
Place sweet potato in a large saucepan with water. Bring to the boil and cook for 15-20 minutes or until tender. Before draining sweet potato, place spinach in the saucepan for 30 seconds or until just wilted.
Drain sweet potato and spinach and place into a medium-sized bowl. Ensure most of the moisture has been drained/squeezed out of the spinach. Mash sweet potato with a fork and set aside to cool for 10 minutes.
Once cooled, place mashed sweet potato, spinach, ricotta, eggs, and mint in a large bowl and stir to combine.
Spray 1 pastry sheet with oil. Fold in half. Spray with oil then fold in half again. Press pastry square into 1 pie dish. Repeat with remaining pastry and pie dishes.
Divide the sweet potato mixture into the pie dishes. Place 4 pie dishes onto a baking tray and bake for 20-30 minutes or until the pastry is golden and the mixture is just set.
Once cooled, place individual pies into resealable freezer bags, plastic wrap or airtight containers and place in the freezer.
Once defrosted, reheat pies in an oven until heated through;
Evenly sprinkle toasted pepitas and sunflower seeds on pies before serving.