01 - Preheat oven to 350°F. Lightly grease a 9x13 inch baking dish with cooking spray or oil.
02 - Remove phyllo sheets from packaging and let them air-dry for 1 hour until slightly crisp. Crumple into rough, irregular pieces by hand.
03 - Whisk eggs and sugar in large bowl until pale and thick, about 3 minutes. Add yogurt, oil, vanilla, orange zest, and baking powder. Mix until fully combined and smooth.
04 - Gradually fold crumpled phyllo pieces into batter, ensuring each piece is evenly coated. The mixture will seem dry but moisture releases during baking.
05 - Pour mixture into prepared baking dish. Spread evenly and smooth surface. Bake 40-45 minutes until golden brown and skewer inserted in center comes out clean.
06 - While pie bakes, combine water, sugar, orange juice, cinnamon stick, and orange zest in saucepan. Bring to boil over high heat, then reduce to medium and simmer 8 minutes until slightly thickened. Remove cinnamon and zest; let syrup cool completely.
07 - Remove pie from oven when done. While still hot, slowly pour cooled syrup evenly over entire surface. Let cool to room temperature, then refrigerate at least 2 hours to allow full absorption before serving.