01 - Preheat the oven to 350°F. Lightly grease a 9x13 inch baking dish with butter or cooking spray.
02 - Remove phyllo sheets from packaging and let them air-dry for 1 hour to become slightly crisp. Crumple the dried sheets into rough, loose pieces by hand.
03 - In a large bowl, whisk together eggs and sugar until pale and thickened, about 3 minutes. Add yogurt, oil, vanilla extract, orange zest, and baking powder. Whisk until smooth and fully combined.
04 - Gradually fold the crumpled phyllo pieces into the batter, gently mixing until all pieces are evenly coated. Be careful not to overmix and tear the phyllo further.
05 - Pour the mixture into the prepared baking dish and spread evenly. Bake for 40-45 minutes until golden brown on top and a skewer inserted in the center comes out clean.
06 - While the pie bakes, combine water, sugar, orange juice, cinnamon stick, and orange zest in a saucepan. Bring to a boil over medium-high heat, then reduce heat and simmer for 8 minutes until slightly thickened. Remove cinnamon stick and orange zest; allow syrup to cool completely.
07 - Remove the baked pie from the oven. While still hot, slowly pour the cooled syrup evenly over the entire surface. Let the pie absorb the syrup for at least 2 hours before serving.