1. Preheat the oven to 200°C. Brush the 1/4 teaspoon oil over a baking tray.
2. Heat 1 tablespoon water in a large saucepan and add the carrots, spring onions, spinach and garlic. Cover and cook over a medium heat for 5 minutes, stirring occasionally. Remove from the heat and set aside to cool.
3. Mix the ricotta, parmesan and egg white in a bowl, then combine with the vegetable mixture, pepper and nutmeg.
4. Work with 4 sheets of pastry at a time. Spread out 2 sheets of pastry on the bench and brush lightly with oil. Top with another two sheets of pastry and brush with oil.
5. Arrange half of the vegetable mixture in a row along the edge of the pastry closest to you, extending it right to the edges. Roll the pastry up firmly to form a long roll. Using a sharp knife, cut the roll into 3 or 6 slices. Repeat with the remaining pastry, oil and filling.
6. Arrange the rolls, seam side down, on the prepared baking tray. Brush with the reserved egg yolk and sprinkle with the sesame seeds.
7. Bake in the preheated oven until the filling is firm and the pastry is golden brown, 12 to 15 minutes.