01 - Preheat the oven to 350°F. Lightly grease a 9x13 inch baking dish with cooking spray or a small amount of oil.
02 - Remove phyllo sheets from packaging and let them dry out at room temperature for 1 hour. Once dried, crumple the sheets into rough, loose pieces by hand.
03 - In a large mixing bowl, whisk together eggs and granulated sugar until pale and thickened, about 3-4 minutes. Add Greek yogurt, oil, vanilla extract, orange zest, and baking powder. Mix until fully combined and smooth.
04 - Gradually fold the crumpled phyllo pieces into the batter, ensuring all pieces are evenly coated. The mixture should be moist but the phyllo should maintain some texture.
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, granulated sugar, fresh 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. Remove from heat, discard cinnamon stick and zest, and let syrup cool completely.
07 - Remove the baked pie from the oven. While still hot, slowly pour the cooled syrup evenly over the entire surface. Allow the pie to soak for at least 2 hours before serving to absorb all the syrup.