In a saucepan over medium-high heat combine the water, sugar, honey and strips of orange zest. Bring to a boil and cook for about 15 minutes. Cover the saucepan and set aside to cool.
Preheat the oven to 375°F Lightly oil an 8x11 baking dish.
Unfold the phyllo dough and tear it into large pieces. Set aside, uncovered, while preparing the rest of the pie.
In a large bowl lightly whisk the eggs. Add the oil, sugar, vanilla, orange zest, yogurt and baking powder and whisk well.
Pour the mixture into the baking dish then add the torn pieces of phyllo, pushing some pieces down slightly to coat.
Bake the pie until set and golden on top, about 30 minutes. Remove from the oven and score lightly into pieces with a sharp knife. Pour the cooled syrup over the top. Let cool it completely before serving.
Serving suggestion: place a piece of portokalopita on a plate and sprinkle with diced candied walnut pieces.