Preheat oven to 350°F. Butter a 9x13-inch baking pan.
Shred the phyllo into thin ribbons. Spread on two sheet pans and air-dry 10–15 minutes, tossing a few times.
Simmer the syrup: combine water, 1 cup sugar, 1/2 cup orange juice, zest strips, and cinnamon. Cook 8–10 minutes until slightly thick.
Stir in honey, remove from heat, and cool completely. Discard zest strips before using.
Whisk eggs and 3/4 cup sugar until pale. Stream in oil, then whisk in yogurt, vanilla, orange zest, and 1/2 cup orange juice.
Whisk in baking powder and salt until smooth.
Fold in dried phyllo a handful at a time, coating evenly without overmixing.
Spread batter in the pan and level the top. Bake 35–40 minutes until deeply golden and set.
Pierce the hot cake all over. Slowly ladle cold syrup over the surface, allowing it to soak in before adding more.
Rest 20 minutes. Garnish with pistachios. Serve warm or at room temperature.