Fluffy Greek orange pie (Portokalopita)

For the base

200 g Greek yogurt 180 g sugar 4 eggs 150 ml olive oil zest from 2–3 oranges 1 tsp vanilla extract 1 tsp baking powder 450 g phyllo pastry (dried and crumbled by hand)

For the syrup

250 g sugar 300 ml orange juice 1 cinnamon stick

For serving

vanilla ice cream orange zest