Spray 2 cookies sheet trays with cooking spray. Put rolls on tray two inches apart. Cover with plastic wrap. When soft, press and cover, let them sit.
Stuffing
Mix spinach, onion, tomatoes, feta cheese, and lemon juice in a bowl. Add salt and pepper to taste.
Put 1 tsp. of stuffing in the middle of the dough. Make sure not to get any juice on the rim of the dough. Pinch corners to make a triangle. Wet rim with butter or water once closed. Brush tops lightly with butter. Bake for 12 minutes or until tops of pies on golden brown and bottoms are cooked.