Preheat oven to 180 degrees & line 2 baking trays with baking paper.
Place the sweet potato on trays & bake for 20-30mins until cook & then remove & add to a bowl
In a large fry pan add some olive oil & add onion & rosemary- cook until soft & then add spinach to wilt - add to the bowl
Increase oven to 200 degrees C
Add feta to the mixture & add a pinch of salt & pepper
Cut each sheet of pastry in half. Place one quarter of the sweet potato mixture in a log shape along one long edge. Brush the opposite long edge with egg. Roll up to enclose.
Cut each roll into 3 pieces and place seam-side down on the prepared trays. Repeat with the remaining sweet potato mixture and pastry
Brush pastry with egg and sprinkle with sesame seeds then bake for 25 minutes or until golden brown